y-cos y=x:(y sin y+cos y+x)y'=y

cos (x + y), sin (x + y), - cos (x + y) sin (xy), cos (xy), sin (xy) sin2x, 0, sin2y] | = sin2 (x + y)

What ( sin x cos y + cos x sin y) (sin x cos y - cos x sin y) equal to ?

Solve the following differential equations y{x cos (y/x)+y sin (y/x)}dx- x{ y sin (y/x)-x cos (y/x)}dy=0 .

Prove that (i) 2 cos x cos y=cos (x+y)+cos (x-y) (ii) -2 . sin x sin y=cos (x+y)-cos (x-y) (iii) 2 sin x cos y=sin (x+y)+sin (x-y) (iv) 2 cos x sin y=sin (x+y)-sin (x-y)

cos4x-cos4y = 8 (cos x-cos y) (cos x + cos y) (cos x-sin y) (cos x + sin y)

{x cos (y/x)+y sin (y/x)} y d x={y sin (y/x)-(x) cos (y/x)} x d y

56.The value of cos^(2)x+cos^(2)y-2cos x cos y cos(x+y) is (A) sin(x+y) (B) sin^(2)(x+y) (C) sin(x+y) (D) sin(x+y)

prove that: cos ^ (2) x + cos ^ (2) y-2cos x * cos y * cos (x + y) = sin ^ (2) (x + y)

[x cos (y / x) + y sin (y / x)] y- [y sin (y / x) -x cos (y / x)] x (dy) / (dx) = 0