`cos4x-cos4y=8(cosx-cosy)(cosx+cosy)(cosx-siny)(cosx+siny)`

(cosx-cosy)^(2)+(sinx-siny)^(2)=?

(sinx-siny)/(cosx+cosy)=tan(x-y)/(2)

If Delta=|(sinx.cosy,sinx.siny,cosx),(cosx.cosy,cosx.siny,-siny),(-sinxsiny,sinx.cosy,0)| , then Delta is independent of a)x b)y c)constant d)None of these

cosx(1+cosy)dx-siny(1+sinx)dy=0

e^(x-y)(sinx+cosx)dx+(cosy-siny)dy=0

What is the value of [(sin x + sin y)(sin x - sin y)]//[(cosx + cosy)(cosy- cosx)] ? [(sin x + sin y)(sin x - sin y)]//[(cosx + cosy)(cosy- cosx)] का मान क्या है?

(cosx+cosy)^(2)|(sinx-siny)^(2)=4cos^(2)(x+y)/(2)

prove (sinx-siny)/(cosx+cosy)=tan(x-y)/2