" 17."cos x-sin x=-1

(cos 9x - cos 5x )/( sin 17 x- sin 3x )=- (sin 2x)/( cos 10x )

(cos 9x - cos 5x )/( sin 17 x- sin 3x )=- (sin 2x)/( cos 10x )

(cos 9x - cos 5x )/( sin 17 x- sin 3x )=- (sin 2x)/( cos 10x )

(cos 9x - cos 5x )/( sin 17 x- sin 3x )=- (sin 2x)/( cos 10x )

Prove that (cos 9 x-cos 5 x)/(sin 17 x-sin 3 x)=-(sin 2 x)/(cos 10 x)

(cos x)/(1-sin x)=(1+cos x+sin x)/(1+cos x-sin x)

Prove that: (i) (1+"sin" 2theta-cos 2theta)/(1+"sin" 2theta+cos 2theta)="tan" theta . (ii) 2 tan 2x=(cos x+"sin" x)/(cos x-"sin" x)-(cos x-"sin" x)/(cos x+"sin" x) .

Prove that : (cos 9x - cos 5x)/(sin 17x -sin 3x)=- (sin 2x)/(cos 10x) .

(cos 9x - cos 5x)/(sin 17x - sin 3x) = (-sin 2x)/(cos 10x)

Prove that: (cos9x-cos5x)/(sin 17 x-sin3x)=\ -(sin2x)/(cos 10 x)