Evaluate the following intergrals
`int_(-pi//2)^(+pi//2) cos x dx`

Options

A. `1`
B. `0`
C. `2`
D. `-1`

Answer

C

Explanation

`overset(+pi//2)underset(-pi//2)int cos x dx= (sin x)_(pi//2)^(+pi//2) = sin (pi)/(2) - sin ((pi)/(2)) = sin(pi)/(2) +sin (pi)/(2) =1+1 =2`
(ii) `overset(pi//3)underset0int sec x tan x dx = (sec x)_0^(pi//3) = sec (pi//3)- sec 0 = 2-1 =1`