Thinking Mathematically (6th Edition)
6th Edition
ISBN: 9780321867322
Author: Robert F. Blitzer
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Videos
Textbook Question
Chapter 1.1, Problem 5E
In Exercises 1-8, find a counterexample to show that each of the statements is false.
Adding the same number to both the numerator and the denominator (top and bottom) of a fraction does not change the fraction’s value.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
Not use ai please
What is the PV of an annuity due with 5 payments of $2,500 at an interest rate of 5.5%?
Question 14 options:
a)
$11,262.88
b)
$11,826.02
c)
$12,417.32
d)
$13,038.19
8
Chapter 1 Solutions
Thinking Mathematically (6th Edition)
Ch. 1.1 - CHECK POINT 1 Find a counterexample to show that...Ch. 1.1 - CHECK POINT 2 Identify a pattern in each list of...Ch. 1.1 - CHECK POINT 3 Identify a pattern in each list of...Ch. 1.1 - CHECK POINT 4 Describe two patterns in this...Ch. 1.1 - CHECK POINT 5 Consider the following procedure:...Ch. 1.1 - The statement 3 + 3 = 6 serves as a/an ________ to...Ch. 1.1 - Arriving at a specific conclusion from one or more...Ch. 1.1 - Arriving at a general conclusion based on...Ch. 1.1 - True or False: A theorem cannot have...Ch. 1.1 - In Exercises 1-8, find a counterexample to show...
Ch. 1.1 - In Exercises 1-8, find a counterexample to show...Ch. 1.1 - In Exercises 1-8, find a counterexample to show...Ch. 1.1 - In Exercises 1-8, find a counterexample to show...Ch. 1.1 - In Exercises 1-8, find a counterexample to show...Ch. 1.1 - In Exercises 1-8, find a counterexample to show...Ch. 1.1 - In Exercises 1-8, find a counterexample to show...Ch. 1.1 - In Exercises 1-8, find a counterexample to show...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, Identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 9-38, identify a pattern in each list...Ch. 1.1 - In Excises 9-38, identify a pattern in each list...Ch. 1.1 - In Exercises 39-42, identify a pattern in each...Ch. 1.1 - In Exercises 39-42, identify a pattern in each...Ch. 1.1 - In Exercises 39-42, identify a pattern in each...Ch. 1.1 - In Exercises 39-42, identify a pattern in each...Ch. 1.1 - Select a number. Multiply the number by 4. Add 8...Ch. 1.1 - Prob. 44ECh. 1.1 - Prob. 45ECh. 1.1 - Prob. 46ECh. 1.1 - In Exercises 47-52, use inductive reasoning to...Ch. 1.1 - In Exercises 47-52, use inductive reasoning to...Ch. 1.1 - In Exercises 47-52, use inductive reasoning to...Ch. 1.1 - Prob. 50ECh. 1.1 - In Exercises 47-52, use inductive reasoning to...Ch. 1.1 - In Exercises 47-52, use inductive reasoning to...Ch. 1.1 - In Exercises 53-54, use inductive reasoning to...Ch. 1.1 - In Exercises 53-54, use inductive reasoning to...Ch. 1.1 - Study the pattern in these examples: a 3 # a 4 = a...Ch. 1.1 - Study the pattern in these examples: a 5 * a 3 * a...Ch. 1.1 - In Exercises 57-60, identify the reasoning...Ch. 1.1 - In Exercises 57-60, identify the reasoning...Ch. 1.1 - Prob. 59ECh. 1.1 - In Exercises 57-60, identify the reasoning...Ch. 1.1 - The ancient Greeks studies figurate numbers, so...Ch. 1.1 - The triangular arrangement of numbers shown below...Ch. 1.1 - Writing about mathematics will help you to learn...Ch. 1.1 - Describe what is meant by deductive reasoning....Ch. 1.1 - Give an example of a decision that you made...Ch. 1.1 - Make Sense? In Exercises 66-69, determine whether...Ch. 1.1 - Make sense? In Exercises 66-69, determine whether...Ch. 1.1 - I used the data shown in the bar graph, which...Ch. 1.1 - I used the data shown in the bar graph for...Ch. 1.1 - If ( 6 − 2 ) 2 = 36 − 24 + 4 and ( 8 − 5 ) 2 = 64...Ch. 1.1 - 71. The rectangle shows an array of nine numbers...Ch. 1.1 - Write a list of numbers that has two patterns so...Ch. 1.1 - a. Repeat the following procedure with at least...Ch. 1.1 - a. Use a calculator to find 6 × 6 , 66 × 66 , 666...Ch. 1.1 - 75. a. Use a calculator to find , and .
b....Ch. 1.1 - Stereotyping refers to classifying people, places,...Ch. 1.2 - CHECKPOINT 1 Round world population...Ch. 1.2 - CHECK POINT 2 Round 3.141592, the first seven...Ch. 1.2 - CHECK POINT 3 You and a friend ate lunch at Ye...Ch. 1.2 - CHECK POINT 4 A Landscape architect who works full...Ch. 1.2 - Prob. 5CPCh. 1.2 - CHECK POINT 6 Use the date for women in Figure 1.5...Ch. 1.2 - Prob. 7CPCh. 1.2 - Prob. 8CPCh. 1.2 - The process of arriving at an approximate answer...Ch. 1.2 - Fill in each blank so that the resulting statement...Ch. 1.2 - Fill in each blank so that the resulting statement...Ch. 1.2 - Fill in each blank so that resulting statement is...Ch. 1.2 - Prob. 5CVCCh. 1.2 - Fill in each blank so that the resulting statement...Ch. 1.2 - Prob. 1ECh. 1.2 - The bar graph gives the 2011 populations of the...Ch. 1.2 - In Exercises 3-8, use this approximation to round...Ch. 1.2 - In Exercises 3-8, use this approximation to round...Ch. 1.2 - In Exercises 3-8, use this approximation to round...Ch. 1.2 - In Exercises 3-8, use this approximation to round...Ch. 1.2 - In Exercises 3-8, use this approximation to round...Ch. 1.2 - In Exercises 3-8, use this approximation to round...Ch. 1.2 - In Exercises 9-34, because different rounding...Ch. 1.2 - In Exercises 9-34, because different rounding...Ch. 1.2 - In Exercises 9-34, because different rounding...Ch. 1.2 - In Exercises 9-34, because different rounding...Ch. 1.2 - In Exercises 9-34, because different rounding...Ch. 1.2 - In Exercises 9-34, because different rounding...Ch. 1.2 - In Exercises 9-34, because different rounding...Ch. 1.2 - In Exercises 9-34, because different rounding...Ch. 1.2 - In Exercises 9-34, because different rounding...Ch. 1.2 - In Exercises 9-34, because different rounding...Ch. 1.2 - In Exercises 9-34, because different rounding...Ch. 1.2 - In Exercises 9-34, because different rounding...Ch. 1.2 - In Exercises 9-34, because different rounding...Ch. 1.2 - In Exercises 9-34, because different rounding...Ch. 1.2 - In Exercises 23-34, determine each estimate...Ch. 1.2 - In Exercises 23-34, determine each estimate...Ch. 1.2 - In Exercises 23-34, determine each estimate...Ch. 1.2 - In Exercises 23-34, determine each estimate...Ch. 1.2 - In Exercises 23-34, determine each estimate...Ch. 1.2 - In Exercises 23-34, determine each estimate...Ch. 1.2 - In Exercises 23-34, determine each estimate...Ch. 1.2 - In Exercises 23-34, determine each estimate...Ch. 1.2 - In Exercises 23-34, determine each estimate...Ch. 1.2 - In Exercises 23-34, determine each estimate...Ch. 1.2 - In Exercises 23-34, determine each estimate...Ch. 1.2 - The average life expectancy in Mozambique is 40.3...Ch. 1.2 - In Exercises 35-36, obtain an estimate for each...Ch. 1.2 - In Exercises 35-36, obtain an estimate for each...Ch. 1.2 - Ten people ordered calculators. The least...Ch. 1.2 - Ten people ordered calculators. The least...Ch. 1.2 - Travelling at an average rate of between 60 and 70...Ch. 1.2 - Prob. 40ECh. 1.2 - 41. Imagine that you counted 60 numbers per minute...Ch. 1.2 - Prob. 42ECh. 1.2 - 43. Without using a calculator, estimate the...Ch. 1.2 - Without using a calculator, estimate the number of...Ch. 1.2 - An online test of English spelling looked at how...Ch. 1.2 - An online test of English spelling looked at how...Ch. 1.2 - The percentage of U.S. college freshmen claiming...Ch. 1.2 - The percentage of U.S. college freshmen claiming...Ch. 1.2 - According to a Gallup poll, in 2012 almost a third...Ch. 1.2 - According to a Gallup poll, in 2012 almost a third...Ch. 1.2 - 51. a. Estimate the yearly increase in the average...Ch. 1.2 - a. Estimate the yearly increase in the average...Ch. 1.2 - Prob. 53ECh. 1.2 - Prob. 54ECh. 1.2 - Explain how to round 14.26841 to the nearest...Ch. 1.2 - Prob. 56ECh. 1.2 - 57. In this era of calculators and computers, why...Ch. 1.2 - Prob. 58ECh. 1.2 - Prob. 59ECh. 1.2 - Prob. 60ECh. 1.2 - Prob. 61ECh. 1.2 - Prob. 62ECh. 1.2 - Prob. 63ECh. 1.2 - Prob. 64ECh. 1.2 - 65. A forecaster at the National Hurricane Center...Ch. 1.2 - Prob. 66ECh. 1.2 - Prob. 67ECh. 1.2 - Prob. 68ECh. 1.2 - Prob. 69ECh. 1.2 - Prob. 70ECh. 1.2 - In Exercises 71-74, match the story with the...Ch. 1.2 - In Exercises 71-74, match the story with the...Ch. 1.2 - In Exercises 71-74, match the story with the...Ch. 1.2 - In Exercises 71-74, match the story with the...Ch. 1.2 - 75. American children ages 2 to 17 spend 19 hours...Ch. 1.2 - Prob. 76ECh. 1.2 - 77. Group members should devise an estimation...Ch. 1.2 - Group members should begin by consulting an...Ch. 1.3 - CHECK POINT 1 Which necessary piece of information...Ch. 1.3 - CHECK POINT 2 Solve the following problem. If the...Ch. 1.3 - CHECK POINT 3 By paying $350 cash up front and the...Ch. 1.3 - CHECK POINT 4 Suppose you are an engineer...Ch. 1.3 - CHECK POINT 5 Your “lecture wardrobe” is rather...Ch. 1.3 - CHECK POINT 6 As in Example 6, a sales director...Ch. 1.3 - The first step in problem solving is to read the...Ch. 1.3 - 2. The second step in problem solving is to ____...Ch. 1.3 - True or False: Polya’s four steps in problem...Ch. 1.3 - True or False: When making a choice between...Ch. 1.3 - In Exercises 1-4, what necessary piece of...Ch. 1.3 - In Exercises 1-4, what necessary piece of...Ch. 1.3 - In Exercises 1-4, what necessary piece of...Ch. 1.3 - In Exercises 1-4, what necessary piece of...Ch. 1.3 - In Exercises 5-8, one more piece of information is...Ch. 1.3 - In Exercises 5-8, one more piece of information is...Ch. 1.3 - In Exercises 5-8, one more piece of information is...Ch. 1.3 - In Exercises 5-8, one more piece of information is...Ch. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Prob. 14ECh. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Prob. 16ECh. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Prob. 20ECh. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Prob. 23ECh. 1.3 - Prob. 24ECh. 1.3 - Prob. 25ECh. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Prob. 30ECh. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Prob. 32ECh. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Prob. 34ECh. 1.3 - Prob. 35ECh. 1.3 - Prob. 36ECh. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Prob. 38ECh. 1.3 - Use Polya’s four-step method in problem solving to...Ch. 1.3 - Prob. 40ECh. 1.3 - Prob. 41ECh. 1.3 - Prob. 42ECh. 1.3 - The map shows five western states. Trace a route...Ch. 1.3 - The layout of a city with land masses and bridges...Ch. 1.3 - Prob. 45ECh. 1.3 - The figure represents a map of 13 countries. If...Ch. 1.3 - Prob. 47ECh. 1.3 - Prob. 48ECh. 1.3 - As in Sudoku, fill in the missing numbers in the...Ch. 1.3 - The missing numbers in the 4-by-4 array are...Ch. 1.3 - Prob. 51ECh. 1.3 - Prob. 52ECh. 1.3 - Prob. 53ECh. 1.3 - In Exercises 52-54, explain the plan needed to...Ch. 1.3 - Prob. 55ECh. 1.3 - Make Sense? In Exercises 56-59, determine whether...Ch. 1.3 - Make Sense? In Exercises 56-59, determine whether...Ch. 1.3 - Make Sense? In Exercises 56-59, determine whether...Ch. 1.3 - Make Sense? In Exercises 56-59, determine whether...Ch. 1.3 - 60. Gym lockers are to be numbered from 1 through...Ch. 1.3 - Prob. 61ECh. 1.3 - Prob. 62ECh. 1.3 - 63. One person tells the truth on Monday, Tuesday,...Ch. 1.3 - Prob. 64ECh. 1.3 - 65. As in Sudoku, fill in the missing numbers...Ch. 1.3 - Prob. 66ECh. 1.3 - Prob. 67ECh. 1.3 - Prob. 68ECh. 1.3 - Prob. 69ECh. 1.3 - Prob. 70ECh. 1.3 - Prob. 71ECh. 1.3 - Prob. 72ECh. 1.3 - Prob. 73ECh. 1.3 - Prob. 74ECh. 1.3 - Group members should describe a problem in need of...Ch. 1 - 1. Which reasoning process is shown in the...Ch. 1 - Prob. 2TCh. 1 - Prob. 3TCh. 1 - Prob. 4TCh. 1 - Prob. 5TCh. 1 - Prob. 6TCh. 1 - Consider the following procedure: Select a number....Ch. 1 - Round 3,279,425 to the nearest hundred thousand.Ch. 1 - Prob. 9TCh. 1 - Prob. 10TCh. 1 - In Exercises 10-13, determine each estimate...Ch. 1 - In Exercises 10-13, determine each estimate...Ch. 1 - Prob. 13TCh. 1 - Prob. 14TCh. 1 - 15. The stated intent of the 1994 “don’t ask,...Ch. 1 - The bar graph shows a dramatic change in the high...Ch. 1 - The cost of renting a boat from Estes Rental is $9...Ch. 1 - Prob. 18TCh. 1 - Prob. 19TCh. 1 - Prob. 20TCh. 1 - 1. Which reasoning process is shown in the...Ch. 1 - 2. Which reasoning process is shown in the...Ch. 1 - In Exercises 3-10, identify a pattern in each list...Ch. 1 - Prob. 4RECh. 1 - In Exercises 3-10, identify a pattern in each list...Ch. 1 - Prob. 6RECh. 1 - Prob. 7RECh. 1 - In Exercises 3-10, identify a pattern in each list...Ch. 1 - Prob. 9RECh. 1 - Prob. 10RECh. 1 - Identify a pattern in the following sequence of...Ch. 1 - In Exercises 12-13, use inductive reasoning to...Ch. 1 - Prob. 13RECh. 1 - Consider the following procedure: Select a number....Ch. 1 - Prob. 15RECh. 1 - Prob. 16RECh. 1 - In Exercises 17-20, obtain an estimate for each...Ch. 1 - In Exercises 17-20, obtain an estimate for each...Ch. 1 - Prob. 19RECh. 1 - Prob. 20RECh. 1 - In Exercises 21-24, determine each estimate...Ch. 1 - In Exercises 21-24, determine each estimate...Ch. 1 - In Exercises 21-24, determine each estimate...Ch. 1 - Prob. 24RECh. 1 - A small private school employs 10 teachers with...Ch. 1 - Prob. 26RECh. 1 - Prob. 27RECh. 1 - 28. The bar graph shows the percentage of people...Ch. 1 - Prob. 29RECh. 1 - The bar graph shows the population of the Unites...Ch. 1 - Prob. 31RECh. 1 - Prob. 32RECh. 1 - Prob. 33RECh. 1 - Use the four-step method in problem solving to...Ch. 1 - Prob. 35RECh. 1 - Prob. 36RECh. 1 - Use the four-step method in problem solving to...Ch. 1 - Use the four-step method in problem solving to...
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, subject and related others by exploring similar questions and additional content below.Similar questions
- The following table describes the distribution of a random sample S of 200 individuals, arranged by education level and income. Income(Dollars per Year) < High School High School Diploma Some College Bachelor’s Degree Graduate Degree Post-Graduate Degree 0-25,000 12 8 3 2 1 0 25,000-50,000 7 12 9 12 11 2 50,000-75,000 1 3 4 6 14 5 75,000-100,000 0 2 1 8 11 8 100,000-125,000 0 1 1 4 8 9 125,000-150,000 0 0 2 3 7 12 150,000+ 0 0 1 1 3 6 Let events be defined as follows: A = the event the subject makes 0-25,000 dollars per yearB = the event the subject makes 25,000-50,000 dollars per year C = the event the subject makes 50,000-75,000 dollars per yearD = the event the subject makes 75,000-100,000 dollars per yearE = the event the subject makes 100,000-125,000 dollars per yearF = the event the subject makes 125,000-150,000 dollars per yearG = the event…arrow_forward2arrow_forward7arrow_forward
- write ur answer with pen in paper must Don't use any Al tool show ur answer in pe n and paper then take Find the value of the integral using residues 2πT dᎾ . Evaluate 32 cos 0+ sin 0 0arrow_forwardProve the following equalities using the residue theorem. Justify your steps. (a) √2 2π de 2πT 0 a + sin ¤ Fa² - 1^ Fa² = π a > 1; 0 (b) 8 x-a π So z +1dx = sin(sa) ୮ 1arrow_forwardApply the Newton-Rapson method to this problem f(x) = -3x² Determine the root using an initial guess at x=1 Perform only four iterations. If convergence is achieved before the fourth iteration, state it clearly. Additionally, provide an explanation as to whether the results are convergent or divergentarrow_forward
- (p). Assume that u(z) is a real harmonic function defined on the disc D(zo, p) = {lz- zolp}. Use Cauchy's integral formula to prove the mean value property: -S u(zo) = [ 2π u(zo + reio) do 27T =arrow_forwardwhat does the central limit theorem, for all samples of the same size n with n>30, the sampling distribution of x can be approximated by a normal distribution mean? What is a real life example using this theoremarrow_forward6. [10] Evaluate (2 (2+2y) ds where C is the upper half-circle centered at the origin connecting the point (2,0) to the point (-2,0). 7. [10] Show that the vector field F(x, y, z) = is conservative and integrate it along the curve П C(t) = si sin t, nt, cost,t), te [0,1] 8. [10] Use Stokes' Theorem to compute the integral curl F.dS, where F(x, y, z) = xzi+yxj+xy k I cur and S is the part of the sphere x² + y²+z² = 9 that lies inside the cylinder x2 + y² above the xy-plane. 9. [10] Use Green's theorem to evaluate So √1+x3 dx+2xy dy where C is the triangle with vertices (0,0), (1, 0) and (1, 3). 10. [10] Evaluate the surface integral (x²z + y²z) dS where S is the hemisphere x² + y²+2² = 4, z> 0. = 1 and ☐arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Holt Mcdougal Larson Pre-algebra: Student Edition...AlgebraISBN:9780547587776Author:HOLT MCDOUGALPublisher:HOLT MCDOUGAL
Algebra: Structure And Method, Book 1AlgebraISBN:9780395977224Author:Richard G. Brown, Mary P. Dolciani, Robert H. Sorgenfrey, William L. ColePublisher:McDougal Littell
Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill
Elementary Geometry For College Students, 7eGeometryISBN:9781337614085Author:Alexander, Daniel C.; Koeberlein, Geralyn M.Publisher:Cengage,
Mathematics For Machine TechnologyAdvanced MathISBN:9781337798310Author:Peterson, John.Publisher:Cengage Learning,
Holt Mcdougal Larson Pre-algebra: Student Edition...
Algebra
ISBN:9780547587776
Author:HOLT MCDOUGAL
Publisher:HOLT MCDOUGAL
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
Glencoe Algebra 1, Student Edition, 9780079039897...
Algebra
ISBN:9780079039897
Author:Carter
Publisher:McGraw Hill
Elementary Geometry For College Students, 7e
Geometry
ISBN:9781337614085
Author:Alexander, Daniel C.; Koeberlein, Geralyn M.
Publisher:Cengage,
Mathematics For Machine Technology
Advanced Math
ISBN:9781337798310
Author:Peterson, John.
Publisher:Cengage Learning,
Understanding Fractions, Improper Fractions, and Mixed Numbers; Author: Professor Dave Explains;https://www.youtube.com/watch?v=qyW2mWvvtZ8;License: Standard YouTube License, CC-BY