Question

The function $f(x)=sinx+cosx,0\leq x\leq 2\pi$ is :

• A. strictly decreasing in $[0,\frac{\pi}{4}]$
• B. strictly Increasing in $[\frac{\pi}{4},\frac{5\pi}{4}]$
• C. strictly decreasing in $[\frac{5\pi}{4},2\pi]$
• D. strictly increasing in $[\frac{5\pi}{4},2\pi]$

Answer 1

Answer: (D)

strictly increasing in $[\frac{5\pi}{4},2\pi]$

Answer 2

The correct option is (D): strictly increasing in $[\frac{5\pi}{4},2\pi]$