For the function f(x)=x2-6x+8,2≤x≤4, then the value of x for whichf'(x) vanishes is
94
52
3
72
Explanation for the correct option:
Step1. Differentiation with respect to x.
f(x)=x2-6x+8,2≤x≤4
⇒f'(x)=2x-6
Step 2. Value of x for whichf'(x) vanishes is
Put f'(x)=0
Then,
2x-6=0
⇒ x=3
Hence, correct option is (C).
If 4sin2x–8sinx+3≤0, then the solution set for x≤0≤x≤2π is