" 4."cosec x=-2

Evaluate the following : lim_(x rarr pi/4)(cosec^2 x-2)/(cot x-1) .

Differentiate the following with respect to x: (i) y=x^3 + 5x^2 + 3x+7 (ii) y=e^(x) + sin x+2 (iii) y=4 cosec x- "log" x-2e^(x)

int (sec^4x.cosec"^2x) dx=

S=cosecx+cosec 2x+cosec 4x+…+cosec 2nx=cot(x/2)−cot2nx

int_(0)^(pi//4) cot x. " cosec"^(2) x dx

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