- #1
zorro
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Homework Statement
Consider the following statements S and R
S : Both sinx and cosx are decreasing functions in the interval (π/2,π)
R : If a differentiable function decreases in an interval (a,b), then its derivative also decreases in (a,b)
Which of the following is/are true?
a) Both S and R are wrong
b) Both S and R are correct but R is not the correct explanation of S
c) R is wrong
d) S is correct
The Attempt at a Solution
S is correct.
I have doubt regarding R.
A function is decreasing iff its derivative is less than 0. I am confused between the 'decreasing of derivative' and 'derivative being less than 0'. Are both same?
I think b and d are correct.