cos((pi)/(4)+x)+cos((pi)/(4)-x)=sqrt(2)cos x

Prove that cos((pi)/(4)+x)+cos((pi)/(4)-x)=sqrt(2)cosx

Prove that, cos((pi)/(4)+x)+cos((pi)/(4)-x)=sqrt(2)cosx .

Prove the following: (i) cos((3pi)/(4)+x)-cos((3pi)/(4)-x)=-sqrt2 sin x (ii) cos"((pi)/(4)+x)+cos((pi)/(4)-x)=sqrt2 cos x .

Prove that : cos((pi)/4+x)+cos((pi)/4-x)=sqrt(2)cosx

cos((3pi)/(4)+x)-cos ((3pi)/(4)-x)=-sqrt(2) sin x

Prove that: cos((3 pi)/(4)+x)-cos((3 pi)/(4)-x)=sqrt(2)sin x

Prove that cos((3pi)/(4)+x)-cos((3pi)/(4)-x)=-sqrt(2)sinx

prove that sin((pi)/(4)+x)+sin((pi)/(4)-x)=sqrt(2)cos x

Prove that: cos((3 pi)/(4)+x)-cos((3 pi)/(4)-x)=-sqrt(2)sin x

Prove that: cos((3 pi)/(4)+x)-cos((3 pi)/(4)-x)=-sqrt(2)sin x