Loading [MathJax]/jax/output/HTML-CSS/jax.js


1)

Value of π/20sinxsinx+cosxdx is


A) π/2

B) π/2

C) π/4

D) None of these

Answer:

Option C

Explanation:

Let I=π/20sinxsinx+cosxdx ...(1)

Then I=π/20sin(π/2x)sin(π/2x)+cos(π/2x)dx

I=π/20cosxcosx+sinxdx...(2)

Adding (1) and (2) we get

2I = π/20sinxcosx+sinxdx + π/20cosxsinx+cosxdx

= π/20cosx+sinxcosx+sinxdx

= π/201.dx=[x](π/2)0 = π/20

I = π/4 = π/20sinxsinx+cosxdx = π/4