Question

The interval in which the $f(x) = sinx-cosx, 0 ≤ x ≤ 2π$ is strictly decreasing is :

• A. $(\frac{π}{4},\frac{5π}{4})$
• B. $(0,\frac{π}{4})∪(\frac{5π}{4},2π)$
• C. $(\frac{3π}{4},\frac{7π}{4})$
• D. $(0,\frac{3π}{4})∪(\frac{7π}{4},2π)$

Answer 1

Answer: (C)

$(\frac{3π}{4},\frac{7π}{4})$

Answer 2

The correct option is (C):

$(\frac{3π}{4},\frac{7π}{4})$