If `y=cos2xcos3x`, then `y_(n)` is equal to

If siny=xcos(a+y) , then (dy)/(dx) is equal to (a) (cos^2(a+y))/(cosa) (b) (cosa)/(cos^2(a+y)) (c) (sin^2y)/(cosa) (d) none of these

If y=cos^(-1)(cosx),t h e n(dy)/(dx) is equal to x/y (b) y/(x^2) (x^2-y^2)/(x^2+y^2) (d) y/x

If y=sin^(2)x.cos^(3)x, then (dy)/(dx)

If y = cos x, then at x = pi/2 , y_2 is equal to

If sin x+sin y=a and cos x+cos y=b, then tan((x+y)/2 ' is equal to

If cosy = xcos (a+y) with cos a ne pm1 , then (dy)/(dx) is equal to

2 cos x cos y is equal to:

(x+y)^(n) + (x-y)^(n) is equal to