Calculus For The Life Sciences
2nd Edition
ISBN: 9780321964038
Author: GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.
Publisher: Pearson Addison Wesley,
expand_more
expand_more
format_list_bulleted
Videos
Question
Chapter 9.CR, Problem 93CR
To determine
(a)
To find:
The approximate change in cost for an additional 1GB of memory for the given condition.
To determine
(b)
To find:
The approximate change in cost for additional hours of labor for the given condition.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
We are constructing a box from a rectangular piece of cardboard. The piece of cardboard which measures 20 inches wide and 58 inches long. We will remove a square of size “x” inches from each corner and turn up the edges.
Once we remove the squares of size “x” inches from each corner and turn up the edges, we create a box: Label the dimensions of the newly created box using the variable “x”.
h=h=
w=w=
l=l=
What is the equation that represents the Volume of the box as a function of the cutsize of the box?
V(x)=Vx=
What is the restricted domain of this problem? (That is, what x values "make sense"?)
≤x≤≤x≤
What is the restricted range of this problem? (That is, what V values "make sense"?)
≤V(x)≤≤Vx≤ (round to 1 decimal place)
To maximize the volume of the newly created box, how much should be cut from each corner?
x=x= inches (round to 1 decimal place)
What is the maximum volume the box can hold?
V=V= in3 (round to 1 decimal…
and R cost
The molarity of a solute in solution is defined to be the number of moles of solute per liter of solution (1 mole = 6.02 × 1023 molecules). If X is the molarity of a solution of sodium chloride (NaCl), and Y is the molarity of a solution of sodium carbonate (Na2CO3), the molarity of sodium ion (Na+)inasolution made of equal parts NaCl and Na2CO3 is given by M = 0.5X + Y. Assume X and Y are independent and normally distributed, and that X has mean 0.450 and standard deviation 0.050, and Y has mean 0.250 and standard deviation 0.025. a) What is the distribution of M? b) Find P(M > 0.5).
Chapter 9 Solutions
Calculus For The Life Sciences
Ch. 9.1 - YOUR TURN For the function in Example 1, find...Ch. 9.1 - Prob. 2YTCh. 9.1 - Prob. 3YTCh. 9.1 - EXERCISES Let f(x,y)=2x3y+5.Find the following. a....Ch. 9.1 - Prob. 2ECh. 9.1 - EXERCISES Let h(x,y)=x2+2y2. Find the following....Ch. 9.1 - EXERCISES Let f(x,y)=9x+5ylogx. Find the...Ch. 9.1 - EXERCISES Let f(x,y)=ex+ln(x+y). Find the...Ch. 9.1 - EXERCISES Let f(x,y)=xex+y. Find the following. a....Ch. 9.1 - EXERCISES Let f(x,y)=xsin(x2y). Find the...
Ch. 9.1 - EXERCISES Let f(x,y)=ycos(x+y).Find the following....Ch. 9.1 - EXERCISES Graph the level curves in the first...Ch. 9.1 - Prob. 18ECh. 9.1 - Prob. 19ECh. 9.1 - Prob. 20ECh. 9.1 - Prob. 21ECh. 9.1 - Prob. 22ECh. 9.1 - Prob. 23ECh. 9.1 - Prob. 24ECh. 9.1 - Prob. 25ECh. 9.1 - Prob. 26ECh. 9.1 - Prob. 27ECh. 9.1 - Prob. 28ECh. 9.1 - Prob. 29ECh. 9.1 - Match each equation in Exercise 2530with its graph...Ch. 9.1 - Prob. 31ECh. 9.1 - Prob. 32ECh. 9.1 - Let f(x,y)=xyex2+y2. Use a graphing calculator or...Ch. 9.1 - The following table provides values of the...Ch. 9.1 - LIFE SCIENCE APPLICATIONS Life Span Researchers...Ch. 9.1 - LIFE SCIENCE APPLICATIONS Heat Loss The rate of...Ch. 9.1 - LIFE SCIENCE APPLICATIONS Body Surface Area The...Ch. 9.1 - LIFE SCIENCE APPLICATIONS Dinosaur Running An...Ch. 9.1 - Prob. 39ECh. 9.1 - Prob. 40ECh. 9.1 - Prob. 41ECh. 9.1 - Agriculture Pregnant sows tethered in stalls often...Ch. 9.1 - Prob. 44ECh. 9.1 - Total Body Water Accurate prediction of total body...Ch. 9.1 - Prob. 46ECh. 9.1 - Prob. 47ECh. 9.1 - Prob. 48ECh. 9.1 - Prob. 49ECh. 9.1 - Prob. 50ECh. 9.2 - YOUR TURN Let f(x,y)=2x2y3+6x5y4. Find fx(x,y) and...Ch. 9.2 - Prob. 2YTCh. 9.2 - Prob. 3YTCh. 9.2 - Prob. 4YTCh. 9.2 - Prob. 1ECh. 9.2 - Prob. 2ECh. 9.2 - Prob. 3ECh. 9.2 - Prob. 4ECh. 9.2 - Prob. 5ECh. 9.2 - Prob. 6ECh. 9.2 - Prob. 7ECh. 9.2 - Prob. 8ECh. 9.2 - Prob. 9ECh. 9.2 - Prob. 10ECh. 9.2 - Prob. 11ECh. 9.2 - Prob. 12ECh. 9.2 - Prob. 13ECh. 9.2 - Prob. 14ECh. 9.2 - Prob. 15ECh. 9.2 - Prob. 16ECh. 9.2 - Prob. 17ECh. 9.2 - Prob. 18ECh. 9.2 - In Exercise 3-22 find fx(x,y)and fy(x,y).Then find...Ch. 9.2 - Prob. 20ECh. 9.2 - Prob. 21ECh. 9.2 - Prob. 22ECh. 9.2 - Prob. 23ECh. 9.2 - Prob. 24ECh. 9.2 - Prob. 25ECh. 9.2 - Prob. 26ECh. 9.2 - Prob. 27ECh. 9.2 - Prob. 28ECh. 9.2 - Prob. 29ECh. 9.2 - Prob. 30ECh. 9.2 - Prob. 31ECh. 9.2 - Prob. 32ECh. 9.2 - Prob. 33ECh. 9.2 - Prob. 34ECh. 9.2 - Prob. 35ECh. 9.2 - Prob. 36ECh. 9.2 - Prob. 37ECh. 9.2 - Prob. 38ECh. 9.2 - Prob. 39ECh. 9.2 - Prob. 40ECh. 9.2 - Prob. 41ECh. 9.2 - Prob. 42ECh. 9.2 - Prob. 43ECh. 9.2 - Prob. 44ECh. 9.2 - Prob. 45ECh. 9.2 - Prob. 46ECh. 9.2 - Prob. 47ECh. 9.2 - Prob. 48ECh. 9.2 - LIFE SCIENCE APPLICATIONS Calorie Expenditure The...Ch. 9.2 - Prob. 50ECh. 9.2 - Prob. 52ECh. 9.2 - Prob. 53ECh. 9.2 - Prob. 54ECh. 9.2 - Prob. 55ECh. 9.2 - Prob. 57ECh. 9.2 - Prob. 58ECh. 9.2 - Prob. 59ECh. 9.2 - Prob. 60ECh. 9.2 - Prob. 62ECh. 9.2 - Prob. 63ECh. 9.2 - Prob. 66ECh. 9.2 - Prob. 67ECh. 9.2 - Prob. 68ECh. 9.2 - Prob. 69ECh. 9.3 - Prob. 1YTCh. 9.3 - Prob. 2YTCh. 9.3 - Prob. 1ECh. 9.3 - Prob. 2ECh. 9.3 - Prob. 3ECh. 9.3 - Prob. 4ECh. 9.3 - Prob. 5ECh. 9.3 - Prob. 7ECh. 9.3 - Prob. 8ECh. 9.3 - Prob. 9ECh. 9.3 - Prob. 10ECh. 9.3 - Find all points where the functions have any...Ch. 9.3 - Prob. 12ECh. 9.3 - Prob. 13ECh. 9.3 - Prob. 14ECh. 9.3 - Prob. 15ECh. 9.3 - Prob. 16ECh. 9.3 - Prob. 17ECh. 9.3 - Prob. 18ECh. 9.3 - Prob. 19ECh. 9.3 - Prob. 20ECh. 9.3 - Prob. 21ECh. 9.3 - Prob. 22ECh. 9.3 - Prob. 23ECh. 9.3 - Prob. 24ECh. 9.3 - Prob. 25ECh. 9.3 - Prob. 26ECh. 9.3 - Prob. 27ECh. 9.3 - Prob. 28ECh. 9.3 - Prob. 29ECh. 9.3 - Let f(x,y)=y22x2y+4x3+20x2. The only critical...Ch. 9.3 - Prob. 31ECh. 9.3 - Prob. 32ECh. 9.3 - Prob. 33ECh. 9.3 - Prob. 34ECh. 9.3 - Prob. 35ECh. 9.3 - Prob. 37ECh. 9.3 - Prob. 38ECh. 9.3 - Prob. 39ECh. 9.3 - Prob. 40ECh. 9.3 - Prob. 41ECh. 9.4 - Prob. 1YTCh. 9.4 - Prob. 2YTCh. 9.4 - Prob. 3YTCh. 9.4 - Evaluate dzusing the given information....Ch. 9.4 - Evaluate dzusing the given information....Ch. 9.4 - Evaluate dzusing the given the information....Ch. 9.4 - Evaluate dzusing the given information....Ch. 9.4 - Multivariable Calculus Total Differentials and...Ch. 9.4 - Evaluate dzusing the given information....Ch. 9.4 - Use the total differential to approximate each...Ch. 9.4 - Use the total differential to approximate each...Ch. 9.4 - Use the total differential to approximate each...Ch. 9.4 - Use the total differential to approximate each...Ch. 9.4 - Use the total differential to approximate each...Ch. 9.4 - Use the total differential to approximate each...Ch. 9.4 - Use the total differential to approximate each...Ch. 9.4 - Use the total differential to approximate each...Ch. 9.4 - Use the total differential to approximate each...Ch. 9.4 - Prob. 16ECh. 9.4 - Blood Vessel Volume A portion of a blood vessel is...Ch. 9.4 - Multivariable Calculus Total Differentials and...Ch. 9.4 - Multivariable Calculus Total Differentials and...Ch. 9.4 - Dialysis A model that estimates the concentration...Ch. 9.4 - Multivariable Calculus Total Differentials and...Ch. 9.4 - Eastern Hemlock Ring shake, which is the...Ch. 9.4 - Multivariable Calculus Total Differentials and...Ch. 9.4 - Multivariable Calculus Total Differentials and...Ch. 9.4 - Multivariable Calculus Total Differentials and...Ch. 9.4 - Prob. 29ECh. 9.4 - Prob. 30ECh. 9.4 - Multivariable Calculus Total Differentials and...Ch. 9.4 - Prob. 32ECh. 9.4 - Prob. 33ECh. 9.4 - Prob. 34ECh. 9.4 - Prob. 35ECh. 9.5 - Prob. 1YTCh. 9.5 - Prob. 2YTCh. 9.5 - Prob. 3YTCh. 9.5 - Prob. 4YTCh. 9.5 - Prob. 5YTCh. 9.5 - Prob. 1ECh. 9.5 - Prob. 2ECh. 9.5 - Prob. 3ECh. 9.5 - Prob. 4ECh. 9.5 - Prob. 5ECh. 9.5 - Prob. 6ECh. 9.5 - Prob. 7ECh. 9.5 - Prob. 8ECh. 9.5 - Prob. 9ECh. 9.5 - EXERCISES Evaluate each integral. 15ye4x+y2dxCh. 9.5 - EXERCISES Evaluate each iterated integral. Many of...Ch. 9.5 - Prob. 12ECh. 9.5 - Prob. 13ECh. 9.5 - Prob. 14ECh. 9.5 - Prob. 15ECh. 9.5 - Prob. 16ECh. 9.5 - Prob. 17ECh. 9.5 - Prob. 18ECh. 9.5 - Prob. 19ECh. 9.5 - Prob. 20ECh. 9.5 - EXERCISES Find each double integral over the...Ch. 9.5 - EXERCISES Find each double integral over the...Ch. 9.5 - Prob. 23ECh. 9.5 - Prob. 24ECh. 9.5 - EXERCISES Find each double integral over the...Ch. 9.5 - Prob. 26ECh. 9.5 - EXERCISES Find each double integral over the...Ch. 9.5 - Prob. 28ECh. 9.5 - Prob. 29ECh. 9.5 - EXERCISES Find each double integral over the...Ch. 9.5 - Prob. 31ECh. 9.5 - Prob. 32ECh. 9.5 - Prob. 33ECh. 9.5 - Prob. 34ECh. 9.5 - Prob. 35ECh. 9.5 - Prob. 36ECh. 9.5 - Prob. 37ECh. 9.5 - Prob. 38ECh. 9.5 - Prob. 39ECh. 9.5 - Prob. 40ECh. 9.5 - Prob. 41ECh. 9.5 - Prob. 42ECh. 9.5 - Prob. 43ECh. 9.5 - Prob. 44ECh. 9.5 - Prob. 45ECh. 9.5 - Prob. 46ECh. 9.5 - Prob. 47ECh. 9.5 - Prob. 48ECh. 9.5 - Prob. 49ECh. 9.5 - Prob. 50ECh. 9.5 - Prob. 51ECh. 9.5 - Prob. 52ECh. 9.5 - EXERCISES Use the region R with the indicated...Ch. 9.5 - EXERCISES Use the region R with the indicated...Ch. 9.5 - Prob. 55ECh. 9.5 - EXERCISES Use the region R with the indicated...Ch. 9.5 - Prob. 57ECh. 9.5 - Prob. 58ECh. 9.5 - Prob. 59ECh. 9.5 - Prob. 60ECh. 9.5 - Prob. 61ECh. 9.5 - Prob. 63ECh. 9.5 - Prob. 64ECh. 9.5 - Prob. 65ECh. 9.5 - Prob. 66ECh. 9.5 - Prob. 67ECh. 9.5 - Prob. 68ECh. 9.5 - Prob. 69ECh. 9.5 - Prob. 70ECh. 9.CR - Determine whether each of the following statements...Ch. 9.CR - Prob. 2CRCh. 9.CR - Prob. 3CRCh. 9.CR - Prob. 4CRCh. 9.CR - Prob. 5CRCh. 9.CR - Prob. 6CRCh. 9.CR - Prob. 7CRCh. 9.CR - Prob. 8CRCh. 9.CR - Prob. 9CRCh. 9.CR - Prob. 10CRCh. 9.CR - Prob. 11CRCh. 9.CR - Prob. 12CRCh. 9.CR - Prob. 13CRCh. 9.CR - Prob. 14CRCh. 9.CR - Prob. 15CRCh. 9.CR - Prob. 16CRCh. 9.CR - Prob. 17CRCh. 9.CR - Prob. 18CRCh. 9.CR - Prob. 19CRCh. 9.CR - Prob. 20CRCh. 9.CR - Prob. 21CRCh. 9.CR - Prob. 22CRCh. 9.CR - Prob. 23CRCh. 9.CR - Prob. 24CRCh. 9.CR - Prob. 25CRCh. 9.CR - Prob. 26CRCh. 9.CR - Prob. 27CRCh. 9.CR - Prob. 28CRCh. 9.CR - Prob. 29CRCh. 9.CR - Prob. 30CRCh. 9.CR - Prob. 31CRCh. 9.CR - Prob. 32CRCh. 9.CR - Prob. 33CRCh. 9.CR - Prob. 34CRCh. 9.CR - Prob. 35CRCh. 9.CR - Prob. 36CRCh. 9.CR - Prob. 37CRCh. 9.CR - Prob. 38CRCh. 9.CR - Prob. 39CRCh. 9.CR - Prob. 40CRCh. 9.CR - Prob. 41CRCh. 9.CR - Prob. 42CRCh. 9.CR - Prob. 43CRCh. 9.CR - Prob. 44CRCh. 9.CR - Prob. 45CRCh. 9.CR - Prob. 46CRCh. 9.CR - Prob. 47CRCh. 9.CR - Prob. 48CRCh. 9.CR - Prob. 49CRCh. 9.CR - Prob. 50CRCh. 9.CR - Prob. 51CRCh. 9.CR - Prob. 52CRCh. 9.CR - Prob. 53CRCh. 9.CR - Prob. 54CRCh. 9.CR - Prob. 55CRCh. 9.CR - Prob. 56CRCh. 9.CR - Prob. 57CRCh. 9.CR - Prob. 58CRCh. 9.CR - Prob. 59CRCh. 9.CR - Prob. 60CRCh. 9.CR - Prob. 61CRCh. 9.CR - Prob. 62CRCh. 9.CR - Prob. 63CRCh. 9.CR - Prob. 64CRCh. 9.CR - Prob. 65CRCh. 9.CR - Prob. 66CRCh. 9.CR - Prob. 67CRCh. 9.CR - Prob. 68CRCh. 9.CR - Prob. 69CRCh. 9.CR - Prob. 70CRCh. 9.CR - Prob. 71CRCh. 9.CR - Prob. 72CRCh. 9.CR - Prob. 73CRCh. 9.CR - Prob. 74CRCh. 9.CR - Prob. 75CRCh. 9.CR - Prob. 76CRCh. 9.CR - Prob. 77CRCh. 9.CR - Prob. 78CRCh. 9.CR - Prob. 79CRCh. 9.CR - Prob. 80CRCh. 9.CR - Prob. 81CRCh. 9.CR - Prob. 82CRCh. 9.CR - Prob. 83CRCh. 9.CR - Prob. 84CRCh. 9.CR - Prob. 85CRCh. 9.CR - Prob. 86CRCh. 9.CR - Prob. 88CRCh. 9.CR - Prob. 89CRCh. 9.CR - Prob. 90CRCh. 9.CR - Prob. 91CRCh. 9.CR - Prob. 92CRCh. 9.CR - Prob. 93CRCh. 9.CR - Prob. 94CRCh. 9.CR - Prob. 95CRCh. 9.CR - Prob. 96CRCh. 9.CR - Prob. 97CRCh. 9.CR - Production Error The height of a sample cone from...Ch. 9.CR - Prob. 99CRCh. 9.EA - Prob. 1EACh. 9.EA - Prob. 2EA
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
- The resistance of a copper wire carrying an electrical current is directly proportional to its length and inversely proportional to its cross-sectional area. A copper wire with a diameter of 0.0126inch has a resistance of 64.9ohms per thousand feet. What length of 0.0201-inch-diameter copper wire will produce a resistance of 33.5ohms?arrow_forwardFind the intensity of light at a depth of 12 meter if I0=14 and k=0.7. Round to two decimals.arrow_forwardFind the unknown value. 27. y varies jointly with x and the cube root of 2. If when x=2 and z=27,y=12, find y if x=5 and z=8.arrow_forward
- All dimensions are in inches. Round the answers to 3 decimal places. a. If y = 2.8000" find x. b If y = 3.000", find x.arrow_forwardd 2t dt 2. Costarrow_forwardThe molarity of a solute in solution is defined to be the number of moles of solute per liter of solution (1 mole = 6.02 × 1023 molecules). If X is the molarity of a solution of magnesium chloride (MgCl2), and Y is the molarity of a solution of ferric chloride (FeCl3), the molarity of chloride ion (Cl−) in a solution made of equal parts of the solutions of MgCl2 and FeCl3 is given by M = X + 1.5Y. Assume that X has mean 0.125 and standard deviation 0.05, and that Y has mean 0.350 and standard deviation 0.10. Find μM.arrow_forward
- The molarity of a solute in solution is defined to be the number of moles of solute per liter of solution (1 mole = 6.02 × 1023 molecules). If X is the molarity of a solution of magnesium chloride (MgCl2), and Y is the molarity of a solution of ferric chloride (FeCl3), the molarity of chloride ion (Cl−) in a solution made of equal parts of the solutions of MgCl2 and FeCl3 is given by M = X + 1.5Y. Assume that X has mean 0.125 and standard deviation 0.05, and that Y has mean 0.350 and standard deviation 0.10 .Assuming X and Y to be independent, find σM.arrow_forward#3arrow_forwardWe are constructing a box from a rectangular piece of cardboard. The piece of cardboard which measures 16 inches wide and 34 inches long. We will remove a square of size “x” inches from each corner and turn up the edges. Once we remove the squares of size “x” inches from each corner and turn up the edges, we create a box: Label the dimensions of the newly created box using the variable “x”. What is the equation that represents the Volume of the box as a function of the cutsize of the box? V(x)=Vx= What is the restricted domain of this problem? (That is, what x values "make sense"?) ≤x≤≤x≤ What is the restricted range of this problem? (That is, what V values "make sense"?) ≤V(x)≤≤Vx≤ (round to 1 decimal place) To maximize the volume of the newly created box, how much should be cut from each corner? x=x= inches (round to 1 decimal place) What is the maximum volume the box can hold? V=V= in3 (round to 1 decimal place) What is the largest…arrow_forward
- We are constructing a box from a rectangular piece of cardboard. The piece of cardboard which measures 16 inches wide and 48 inches long. We will remove a square of size “x” inches from each corner and turn up the edges. Once we remove the squares of size “x” inches from each corner and turn up the edges, we create a box: Label the dimensions of the newly created box using the variable “x”. What is the equation that represents the Volume of the box as a function of the cutsize of the box? V(x)= What is the restricted domain of this problem? (That is, what x values "make sense"?) ≤x≤ What is the restricted range of this problem? (That is, what V values "make sense"?) ≤V(x)≤ (round to 1 decimal place) To maximize the volume of the newly created box, how much should be cut from each corner? x= inches (round to 1 decimal place) What is the maximum volume the box can hold? V= in3 (round to 1 decimal place) What is the largest cutsize you can cut out of the paper and…arrow_forwardAssume a box has a square base and the length of a side of the base is equal to twice the height of the box. a. If the height is 6 inches, what are the dimensions of the base? The dimensions of the base are inches X inches = square inches. b. Write functions for the surface area and the volume that are dependent on the height, h. S(h) = nh" square inches, where n = and m = %3D V(h) = ph° cubic inches where p = and g = %3D c. If the volume has increased by a factor of 27, what has happened to the height? The new height is times the original height. d. As the height increases, what will happen to the ratio of (surface area)/volume? The ratio will not chänge e Textbook Increase decreasearrow_forwardSolve. N = R + V/G for V (Urban forestry: tree plantings per year)arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Algebra & Trigonometry with Analytic GeometryAlgebraISBN:9781133382119Author:SwokowskiPublisher:Cengage
Algebra: Structure And Method, Book 1AlgebraISBN:9780395977224Author:Richard G. Brown, Mary P. Dolciani, Robert H. Sorgenfrey, William L. ColePublisher:McDougal Littell
Mathematics For Machine TechnologyAdvanced MathISBN:9781337798310Author:Peterson, John.Publisher:Cengage Learning,
College Algebra (MindTap Course List)AlgebraISBN:9781305652231Author:R. David Gustafson, Jeff HughesPublisher:Cengage Learning
Algebra & Trigonometry with Analytic Geometry
Algebra
ISBN:9781133382119
Author:Swokowski
Publisher:Cengage
Algebra: Structure And Method, Book 1
Algebra
ISBN:9780395977224
Author:Richard G. Brown, Mary P. Dolciani, Robert H. Sorgenfrey, William L. Cole
Publisher:McDougal Littell
Mathematics For Machine Technology
Advanced Math
ISBN:9781337798310
Author:Peterson, John.
Publisher:Cengage Learning,
College Algebra (MindTap Course List)
Algebra
ISBN:9781305652231
Author:R. David Gustafson, Jeff Hughes
Publisher:Cengage Learning
Solve ANY Optimization Problem in 5 Steps w/ Examples. What are they and How do you solve them?; Author: Ace Tutors;https://www.youtube.com/watch?v=BfOSKc_sncg;License: Standard YouTube License, CC-BY
Types of solution in LPP|Basic|Multiple solution|Unbounded|Infeasible|GTU|Special case of LP problem; Author: Mechanical Engineering Management;https://www.youtube.com/watch?v=F-D2WICq8Sk;License: Standard YouTube License, CC-BY
Optimization Problems in Calculus; Author: Professor Dave Explains;https://www.youtube.com/watch?v=q1U6AmIa_uQ;License: Standard YouTube License, CC-BY
Introduction to Optimization; Author: Math with Dr. Claire;https://www.youtube.com/watch?v=YLzgYm2tN8E;License: Standard YouTube License, CC-BY