If f(x) = |cos x| + |sin x| then dy/dx at x = 2π/3 is
A
(√3 - 1)/2
B
0
C
(1 - √3)/2
D
1
Correct Option:
A
Explanation
At x = 2π/3, sin x > 0 while cos x < 0. Hence f(x) = |cos x| + |sin x| = −cos x + sin x. Therefore, f′(x) = sin x + cos x. At x = 2π/3, f′(x) = √3/2 − 1/2 = (√3 − 1)/2.
