" (b) "int_(-pi/4)^( pi/4)(cosec^(2)x)dx

int_(-pi//4)^(pi//4)cosec^(2)xdx

int_(pi/4)^(pi/2) cosec^(2)x dx =

int_(- pi/4)^(pi/4) cos^(-4) x dx=

int_(-pi/4)^(pi/4)(secx)/(1+2^(x))dx .

int_(-pi//4)^(pi//4) sin^(2) x dx

int_(-pi//4)^(pi//4)sin^(2)x dx=

(i) int_0^(pi//2) sin^2 dx =pi/4 (ii) int_0^(pi//2) cos^2x dx=pi/4 (iii) int_(-pi//4)^(pi//4) sin^2 x dx=pi/4-1/2 (iv) int_(-pi//4)^(pi//4) cos^2x dx=pi/4+1/2

int_(pi//4)^(pi//2)cot^(2)x dx =

int_(pi//6)^(pi//4)cosec 2x dx=

int_(pi//6)^(pi//4)cosec 2x dx=