MyLab Math with Pearson eText -- Standalone Access Card -- for Calculus: Early Transcendentals (3rd Edition)
3rd Edition
ISBN: 9780134856926
Author: William L. Briggs, Lyle Cochran, Bernard Gillett, Eric Schulz
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 7.2, Problem 41E
Tumor growth Suppose the cells of a tumor are idealized as spheres each with a radius of 5 μm (micrometers). The number of cells has a doubling time of 35 days. Approximately how long will it take a single cell to grow into a multi-celled spherical tumor with a volume of 0.5 cm3 (1 cm = 10,000 μm)? Assume that the tumor spheres are tightly packed.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
An explosion at an oil rig located in gulf waters causesan elliptical oil slick to spread on the surface from the rig. The slickis a constant 9 in. thick. After several days, when the major axis ofthe slick is 2 mi long and the minor axis is 3/4 mi wide, it is determinedthat its length is increasing at the rate of 30 ft/hr, and itswidth is increasing at the rate of 10 ft/hr. At what rate (in cubic feetper hour) is oil flowing from the site of the rig at that time?
A water reservoir has the shape of a right circular cone with its circular base of radius R = 160 m at ground
level (z = 0 m). Rain fills the reservoir over the winter; when full, the reservoir depth is h =
summer, water from the reservoir is pumped up to ground level for drinking, irrigation, etc. At the end of the
summer, the volume of water left in the reservoir is only 3/7 of its full capacity.
%3D
70 m. In
(a) Find the depth of the water in the reservoir at the end of the summer.
Answer: Depth = 52.776
m
(b) Find the total work done to lift water out of the reservoir during the summer.
Answer: W = 54461207640
J.
(Recall the density of fresh water: p =
1000 kg/m.)
Remaining Time: 1 hour, 03 minutes, 12 seconds.
* Question Completion Status:
Moving to another question will save this response.
Question 19
The radius of a spherical balloon is measured as 10 inches, with a
maximum error in measurement of ± 0.05 inch. Approximate the
maximum error in the calculated volume of the sphere.
O a. dv = ±20
O b. dv = - 20 Tt
Oc dv= ±20 T
Od. dv =20 T
A Moving to another question will save this response.
Chapter 7 Solutions
MyLab Math with Pearson eText -- Standalone Access Card -- for Calculus: Early Transcendentals (3rd Edition)
Ch. 7.1 - What is the domain of ln |x|?Ch. 7.1 - Simplify e ln 2x, ln (e2x), e2 ln x, and ln (2ex)Ch. 7.1 - What is the slope of the curve y = ex at x= ln 2?...Ch. 7.1 - Verify that the derivative and integral results...Ch. 7.1 - Prob. 1ECh. 7.1 - Prob. 2ECh. 7.1 - Evaluate 4xdx.Ch. 7.1 - What is the inverse function of ln x, and what are...Ch. 7.1 - Express 3x, x, and xsin x using the base e.Ch. 7.1 - Evaluate ddx(3x).
Ch. 7.1 - Derivatives Evaluate the following derivatives...Ch. 7.1 - Derivatives with ln x Evaluate the following...Ch. 7.1 - Derivatives with ln x Evaluate the following...Ch. 7.1 - Derivatives with ln x Evaluate the following...Ch. 7.1 - Derivatives with ln x Evaluate the following...Ch. 7.1 - Derivatives with ln x Evaluate the following...Ch. 7.1 - Derivatives Evaluate the derivatives of the...Ch. 7.1 - Derivatives Evaluate the derivatives of the...Ch. 7.1 - Derivatives Evaluate the derivatives of the...Ch. 7.1 - Derivatives Evaluate the derivatives of the...Ch. 7.1 - Derivatives Evaluate the derivatives of the...Ch. 7.1 - Derivatives Evaluate the derivatives of the...Ch. 7.1 - Derivatives Evaluate the derivatives of the...Ch. 7.1 - Derivatives Evaluate the derivatives of the...Ch. 7.1 - Miscellaneous derivatives Compute the following...Ch. 7.1 - Miscellaneous derivatives Compute the following...Ch. 7.1 - Miscellaneous derivatives Compute the following...Ch. 7.1 - Prob. 24ECh. 7.1 - Miscellaneous derivatives Compute the following...Ch. 7.1 - Miscellaneous derivatives Compute the following...Ch. 7.1 - Miscellaneous derivatives Compute the following...Ch. 7.1 - Miscellaneous derivatives Compute the following...Ch. 7.1 - Integrals with ln x Evaluate the following...Ch. 7.1 - Integrals Evaluate the following integrals....Ch. 7.1 - Integrals with ln x Evaluate the following...Ch. 7.1 - Integrals with ln x Evaluate the following...Ch. 7.1 - Integrals with ln x Evaluate the following...Ch. 7.1 - Integrals with ln x Evaluate the following...Ch. 7.1 - Integrals with ln x Evaluate the following...Ch. 7.1 - Integrals with ln x Evaluate the following...Ch. 7.1 - Integrals with ex Evaluate the following...Ch. 7.1 - Integrals with ex Evaluate the following...Ch. 7.1 - Integrals with ex Evaluate the following...Ch. 7.1 - Integrals with ex Evaluate the following...Ch. 7.1 - Integrals with ex Evaluate the following...Ch. 7.1 - Integrals with ex Evaluate the following...Ch. 7.1 - Integrals with general bases Evaluate the...Ch. 7.1 - Integrals with general bases Evaluate the...Ch. 7.1 - Integrals with general bases Evaluate the...Ch. 7.1 - Integrals with general bases Evaluate the...Ch. 7.1 - Integrals with general bases Evaluate the...Ch. 7.1 - Integrals with general bases Evaluate the...Ch. 7.1 - Integrals Evaluate the following integrals....Ch. 7.1 - Miscellaneous integrals Evaluate the following...Ch. 7.1 - Miscellaneous integrals Evaluate the following...Ch. 7.1 - Miscellaneous integrals Evaluate the following...Ch. 7.1 - Miscellaneous integrals Evaluate the following...Ch. 7.1 - Miscellaneous integrals Evaluate the following...Ch. 7.1 - Miscellaneous integrals Evaluate the following...Ch. 7.1 - Miscellaneous integrals Evaluate the following...Ch. 7.1 - Miscellaneous integrals Evaluate the following...Ch. 7.1 - Miscellaneous integrals Evaluate the following...Ch. 7.1 - Miscellaneous integrals Evaluate the following...Ch. 7.1 - Integrals Evaluate the following integrals....Ch. 7.1 - Integrals Evaluate the following integrals....Ch. 7.1 - Miscellaneous integrals Evaluate the following...Ch. 7.1 - Calculator limits Use a calculator to make a table...Ch. 7.1 - Calculator limits Use a calculator to make a table...Ch. 7.1 - Calculator limits Use a calculator to make a table...Ch. 7.1 - Calculator limits Use a calculator to make a table...Ch. 7.1 - Prob. 67ECh. 7.1 - Prob. 68ECh. 7.1 - Prob. 69ECh. 7.1 - Prob. 70ECh. 7.1 - Prob. 71ECh. 7.1 - Prob. 72ECh. 7.1 - Prob. 73ECh. 7.1 - Prob. 74ECh. 7.1 - Prob. 75ECh. 7.1 - Prob. 76ECh. 7.1 - Harmonic sum In Chapter 10, we will encounter the...Ch. 7.1 - Probability as an integral Two points P and Q are...Ch. 7.2 - Population A increases at a constant rate of...Ch. 7.2 - Verify that the time needed for y(t) = y0ekt. to...Ch. 7.2 - Assume y() 100e0.005, 3y (exactly) what...Ch. 7.2 - If a quantity decreases by a factor of 8 every 30...Ch. 7.2 - In terms of relative growth rate, what is the...Ch. 7.2 - Prob. 2ECh. 7.2 - Prob. 3ECh. 7.2 - Prob. 4ECh. 7.2 - Prob. 5ECh. 7.2 - Prob. 6ECh. 7.2 - Suppose a quantity described by the function y(t)...Ch. 7.2 - Suppose a quantity is described by the function...Ch. 7.2 - Give two examples of processes that are modeled by...Ch. 7.2 - Give two examples of processes that are modeled by...Ch. 7.2 - Because of the absence of predators, the number of...Ch. 7.2 - After the introduction of foxes on an island, the...Ch. 7.2 - Absolute and relative growth rates Two functions f...Ch. 7.2 - Absolute and relative growth rates Two functions f...Ch. 7.2 - Designing exponential growth functions Complete...Ch. 7.2 - Designing exponential growth functions Complete...Ch. 7.2 - Designing exponential growth functions Complete...Ch. 7.2 - Designing exponential growth functions Complete...Ch. 7.2 - Designing exponential growth functions Complete...Ch. 7.2 - Designing exponential growth functions Complete...Ch. 7.2 - Determining APY Suppose 1000 is deposited in a...Ch. 7.2 - Tortoise growth In a study conducted at University...Ch. 7.2 - Projection sensitivity According to the 2014...Ch. 7.2 - Energy consumption On the first day of the year (t...Ch. 7.2 - Population of Texas Texas was the third fastest...Ch. 7.2 - Oil consumption Starting in 2018 (t = 0), the rate...Ch. 7.2 - Designing exponential decay functions Devise an...Ch. 7.2 - Designing exponential decay functions Devise an...Ch. 7.2 - Designing exponential decay functions Devise an...Ch. 7.2 - Designing exponential decay functions Devise an...Ch. 7.2 - Population of West Virginia The population of West...Ch. 7.2 - Prob. 32ECh. 7.2 - Atmospheric pressure The pressure of Earths...Ch. 7.2 - Carbon dating The half-life of C-14 is about 5730...Ch. 7.2 - Uranium dating Uranium-238 (U-238) has a half-life...Ch. 7.2 - Radioiodine treatment Roughly 12,000 Americans are...Ch. 7.2 - Caffeine After an individual drinks a beverage...Ch. 7.2 - Caffeine After an individual drinks a beverage...Ch. 7.2 - Prob. 39ECh. 7.2 - Prob. 40ECh. 7.2 - Tumor growth Suppose the cells of a tumor are...Ch. 7.2 - Tripling time A quantity increases according to...Ch. 7.2 - Explain why or why not Determine whether the...Ch. 7.2 - A running model A model for the startup of a...Ch. 7.2 - Prob. 45ECh. 7.2 - Prob. 46ECh. 7.2 - A slowing race Starting at the same time and...Ch. 7.2 - Prob. 48ECh. 7.2 - Compounded inflation The U.S. government reports...Ch. 7.2 - Acceleration, velocity, position Suppose the...Ch. 7.2 - Air resistance (adapted from Putnam Exam, 1939) An...Ch. 7.2 - General relative growth rates Define the relative...Ch. 7.2 - Equivalent growth functions The same exponential...Ch. 7.2 - Geometric means A quantity grows exponentially...Ch. 7.2 - Constant doubling time Prove that the doubling...Ch. 7.3 - Use the definition of the hyperbolic sine to show...Ch. 7.3 - Explain why the graph of tanh x has the horizontal...Ch. 7.3 - Find both the derivative and indefinite integral...Ch. 7.3 - Prob. 4QCCh. 7.3 - Prob. 5QCCh. 7.3 - Prob. 6QCCh. 7.3 - Explain why longer waves travel faster than...Ch. 7.3 - State the definition of the hyperbolic cosine and...Ch. 7.3 - Sketch the graphs of y = cosh x, y sinh x, and y...Ch. 7.3 - What is the fundamental identity for hyperbolic...Ch. 7.3 - Prob. 4ECh. 7.3 - Express sinh1 x in terms of logarithms.Ch. 7.3 - Prob. 6ECh. 7.3 - Prob. 7ECh. 7.3 - On what interval is the formula d/dx (tanh1 x) =...Ch. 7.3 - Prob. 9ECh. 7.3 - Prob. 10ECh. 7.3 - Verifying identities Verify each identity using...Ch. 7.3 - Verifying identities Verify each identity using...Ch. 7.3 - Verifying identities Verify each identity using...Ch. 7.3 - Verifying identities Verify each identity using...Ch. 7.3 - Verifying identities Verify each identity using...Ch. 7.3 - Verifying identities Use the given identity to...Ch. 7.3 - Verifying identities Use the given identity to...Ch. 7.3 - Prob. 18ECh. 7.3 - Derivative formulas Derive the following...Ch. 7.3 - Derivative formulas Derive the following...Ch. 7.3 - Derivative formulas Derive the following...Ch. 7.3 - Derivatives Compute dy/dx for the following...Ch. 7.3 - Derivatives Compute dy/dx for the following...Ch. 7.3 - Derivatives Compute dy/dx for the following...Ch. 7.3 - Derivatives Compute dy/dx for the following...Ch. 7.3 - Derivatives Compute dy/dx for the following...Ch. 7.3 - Derivatives Compute dy/dx for the following...Ch. 7.3 - Derivatives Compute dy/dx for the following...Ch. 7.3 - Derivatives Compute dy/dx for the following...Ch. 7.3 - Prob. 30ECh. 7.3 - Derivatives Find the derivatives of the following...Ch. 7.3 - Derivatives Find the derivatives of the following...Ch. 7.3 - Derivatives Find the derivatives of the following...Ch. 7.3 - Derivatives Find the derivatives of the following...Ch. 7.3 - Prob. 35ECh. 7.3 - Prob. 36ECh. 7.3 - Indefinite integrals Determine each indefinite...Ch. 7.3 - Integrals Evaluate each integral. sech2wtanhwdwCh. 7.3 - Indefinite integrals Determine each indefinite...Ch. 7.3 - Indefinite integrals Determine each indefinite...Ch. 7.3 - Indefinite integrals Determine each indefinite...Ch. 7.3 - Indefinite integrals Determine each indefinite...Ch. 7.3 - Definite integrals Evaluate each definite...Ch. 7.3 - Integrals Evaluate each integral. 0ln2sech2xxdxCh. 7.3 - Definite integrals Evaluate each definite...Ch. 7.3 - Definite integrals Evaluate each definite...Ch. 7.3 - Indefinite integrals Determine the following...Ch. 7.3 - Integrals Evaluate each integral. 48.dxx216,x4Ch. 7.3 - Indefinite integrals Determine the following...Ch. 7.3 - Prob. 50ECh. 7.3 - Indefinite integrals Determine the following...Ch. 7.3 - Prob. 52ECh. 7.3 - Additional integrals Evaluate the following...Ch. 7.3 - Additional integrals Evaluate the following...Ch. 7.3 - Prob. 55ECh. 7.3 - Additional integrals Evaluate the following...Ch. 7.3 - Two ways Evaluate the following integrals two...Ch. 7.3 - Two ways Evaluate the following integrals two...Ch. 7.3 - Visual approximation a. Use a graphing utility to...Ch. 7.3 - Prob. 60ECh. 7.3 - Prob. 61ECh. 7.3 - Points of intersection and area a. Sketch the...Ch. 7.3 - Definite integrals Evaluate the following definite...Ch. 7.3 - Definite integrals Evaluate the following definite...Ch. 7.3 - Definite integrals Evaluate the following definite...Ch. 7.3 - Prob. 66ECh. 7.3 - Prob. 67ECh. 7.3 - Prob. 68ECh. 7.3 - Catenary arch The portion of the curve y=1716coshx...Ch. 7.3 - Length of a catenary Show that the arc length of...Ch. 7.3 - Power lines A power line is attached at the same...Ch. 7.3 - Sag angle Imagine a climber clipping onto the rope...Ch. 7.3 - Wavelength The velocity of a surface wave on the...Ch. 7.3 - Prob. 74ECh. 7.3 - Prob. 75ECh. 7.3 - Prob. 76ECh. 7.3 - Explain why or why not Determine whether the...Ch. 7.3 - Evaluating hyperbolic functions Use a calculator...Ch. 7.3 - Evaluating hyperbolic functions Evaluate each...Ch. 7.3 - Prob. 80ECh. 7.3 - Critical points Find the critical points of the...Ch. 7.3 - Critical points a. Show that the critical points...Ch. 7.3 - Points of inflection Find the x-coordinate of the...Ch. 7.3 - Prob. 84ECh. 7.3 - Area of region Find the area of the region bounded...Ch. 7.3 - Prob. 86ECh. 7.3 - LHpital loophole Explain why lHpitals Rule fails...Ch. 7.3 - Limits Use lHpitals Rule to evaluate the following...Ch. 7.3 - Limits Use lHpitals Rule to evaluate the following...Ch. 7.3 - Prob. 90ECh. 7.3 - Prob. 91ECh. 7.3 - Prob. 92ECh. 7.3 - Kiln design Find the volume interior to the...Ch. 7.3 - Prob. 94ECh. 7.3 - Falling body When an object falling from rest...Ch. 7.3 - Prob. 96ECh. 7.3 - Prob. 97ECh. 7.3 - Prob. 98ECh. 7.3 - Differential equations Hyperbolic functions are...Ch. 7.3 - Prob. 100ECh. 7.3 - Prob. 101ECh. 7.3 - Prob. 102ECh. 7.3 - Prob. 103ECh. 7.3 - Prob. 104ECh. 7.3 - Prob. 105ECh. 7.3 - Theorem 7.8 a. The definition of the inverse...Ch. 7.3 - Prob. 107ECh. 7.3 - Prob. 108ECh. 7.3 - Arc length Use the result of Exercise 108 to find...Ch. 7.3 - Prob. 110ECh. 7.3 - Prob. 111ECh. 7.3 - Definitions of hyperbolic sine and cosine Complete...Ch. 7 - Explain why or why not Determine whether the...Ch. 7 - Integrals Evaluate the following integrals. 56....Ch. 7 - Integrals Evaluate the following integrals. 57....Ch. 7 - Integrals Evaluate the following integrals. 58....Ch. 7 - Integrals Evaluate the following integrals. 59....Ch. 7 - Integrals Evaluate the following integrals. 60....Ch. 7 - Integrals Evaluate the following integrals. 61....Ch. 7 - Integrals Evaluate the following integrals. 62....Ch. 7 - Integrals Evaluate the following integrals. 63....Ch. 7 - Derivatives Find the derivatives of the following...Ch. 7 - Derivatives Find the derivatives of the following...Ch. 7 - Derivatives Find the derivatives of the following...Ch. 7 - Derivatives Find the derivatives of the following...Ch. 7 - Prob. 14RECh. 7 - Prob. 15RECh. 7 - Derivatives Find the derivatives of the following...Ch. 7 - Prob. 17RECh. 7 - Prob. 18RECh. 7 - Prob. 19RECh. 7 - Population growth The population of a large city...Ch. 7 - Caffeine An adult consumes an espresso containing...Ch. 7 - Two cups of coffee A college student consumed two...Ch. 7 - Moores Law In 1965, Gordon Moore observed that the...Ch. 7 - Radioactive decay The mass of radioactive material...Ch. 7 - Population growth Growing from an initial...Ch. 7 - Prob. 26RECh. 7 - Prob. 27RECh. 7 - Curve sketching Use the graphing techniques of...Ch. 7 - Prob. 29RECh. 7 - Prob. 30RECh. 7 - Linear approximation Find the linear approximation...Ch. 7 - Limit Evaluate limx(tanhx)x.Ch. 7 - Derivatives of hyperbolic functions Compute the...Ch. 7 - Arc length Find the arc length of the curve y = ln...
Additional Math Textbook Solutions
Find more solutions based on key concepts
Suppose that A and B are mutually exclusive events for which P(A) = .3 and P(B) = .5. What is the probability t...
A First Course in Probability (10th Edition)
In Exercises 25–28, use the confidence interval to find the margin of error and the sample mean.
25. (12.0, 14....
Elementary Statistics: Picturing the World (7th Edition)
the number of hours of practice for 15 and 22 school days.
Pre-Algebra Student Edition
CHECK POINT I Express as a percent.
Thinking Mathematically (6th Edition)
Consider the Source. In Exercises 5–8, determine whether the given source has the potential to create a bias in...
Elementary Statistics (13th Edition)
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, calculus and related others by exploring similar questions and additional content below.Similar questions
- Cycling The Campagnolo Hyperon Ultra Two carbon wheel, which has a diameter of 700 millimeters, has 22 spokes evenly distributed around the rim of the wheel. What is the length of the rim subtended by adjacent pairs of spokes (Figure 15)?arrow_forwardSolve these prism and cylinder exercises. Where necessary, round the answers to 2 decimal places unless otherwise specified. Compute the volume of a prism with a base area of 220.0 square centimeters and a height of 7.600 centimeters.arrow_forwardSolve these prism and cylinder exercises. Where necessary, round the answers to 2 decimal places unless otherwise specified. The frustum of a right circular cone has a larger base area of 40.0 square centimeters and a smaller base area of 19.0 square centimeters. The height is 22.0 centimeters. Find the volume. Round the answer to the nearest cubic centimeter.arrow_forward
- Solve these prism and cylinder exercises. Where necessary, round the answers to 2 decimal places unless otherwise specified. Find the volume of a right circular cylinder that has a height of 4,600 inches and a base area of 53.00 square inches.arrow_forwardSolve these prism and cylinder exercises. Where necessary, round the answers to 2 decimal places unless otherwise specified. A solid right cylinder 9.55 centimeters high contains 1910 cubic centimeters of material. Compute the cross-sectional area of the cylinder.arrow_forwardThe tin can shown at the right has the indicated dimensions. Estimate the number of square inches of tin required for its construction. HINT: Include the lid and the base in the result.arrow_forward
- Solve these prism and cylinder exercises. Where necessary, round the answers to 2 decimal places unless otherwise specified. A solid brass casting in the shape of a right circular cone has a base diameter of 4.36 inches and a height of 3.94 inches. Find the weight of the casting. Brass weighs 0.302 pound per cubic inch.arrow_forwardA basketball has a volume of about 455.9 cubic inches. Find the radius of the basketball (accurate to three decimal places).arrow_forwardFind inside caliper dimension x. All dimensions are in inches.arrow_forward
- The kinetic energy E of an object varies jointly with the object’s mass m and the square of the object’s velocity v . An object with a mass of 50 kilograms traveling at 16 meters per second has a kinetic energy of 6400 joules. What is the kinetic energy of an object with a mass of 70 kilograms traveling at 20 meters per second?arrow_forwardPlease recheck and provide clear and complete step-by-step solution in scanned handwriting or computerized output thank youarrow_forwardA trough is 9 meters long, 3 meters wide, and 2 meters deep. The vertical cross-section of the trough parallel to an end is shaped like an isoceles triangle (with height 2 meters, and kg base, on top, of length 3 meters). The trough is full of water (density 1000- ). Find m the amount of work in joules required to empty the trough by pumping the water over the top. (Note: Use g = 9.8- as the acceleration due to gravity.) m 8² Joulesarrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Mathematics For Machine TechnologyAdvanced MathISBN:9781337798310Author:Peterson, John.Publisher:Cengage Learning,
Trigonometry (MindTap Course List)TrigonometryISBN:9781305652224Author:Charles P. McKeague, Mark D. TurnerPublisher:Cengage Learning
Elementary Geometry For College Students, 7eGeometryISBN:9781337614085Author:Alexander, Daniel C.; Koeberlein, Geralyn M.Publisher:Cengage,
Elementary Geometry for College StudentsGeometryISBN:9781285195698Author:Daniel C. Alexander, Geralyn M. KoeberleinPublisher:Cengage Learning
Mathematics For Machine Technology
Advanced Math
ISBN:9781337798310
Author:Peterson, John.
Publisher:Cengage Learning,
Trigonometry (MindTap Course List)
Trigonometry
ISBN:9781305652224
Author:Charles P. McKeague, Mark D. Turner
Publisher:Cengage Learning
Elementary Geometry For College Students, 7e
Geometry
ISBN:9781337614085
Author:Alexander, Daniel C.; Koeberlein, Geralyn M.
Publisher:Cengage,
Elementary Geometry for College Students
Geometry
ISBN:9781285195698
Author:Daniel C. Alexander, Geralyn M. Koeberlein
Publisher:Cengage Learning
01 - What Is A Differential Equation in Calculus? Learn to Solve Ordinary Differential Equations.; Author: Math and Science;https://www.youtube.com/watch?v=K80YEHQpx9g;License: Standard YouTube License, CC-BY
Higher Order Differential Equation with constant coefficient (GATE) (Part 1) l GATE 2018; Author: GATE Lectures by Dishank;https://www.youtube.com/watch?v=ODxP7BbqAjA;License: Standard YouTube License, CC-BY
Solution of Differential Equations and Initial Value Problems; Author: Jefril Amboy;https://www.youtube.com/watch?v=Q68sk7XS-dc;License: Standard YouTube License, CC-BY