If `a=cos phi cos psi+sin phi sin psi cos delta, \ b=cos phi sin psi-sin phi cos psi cos delta, \ "and" \ c=sin phi sin delta`, then `a^2+b^2+c^2=`

If x = cos theta cos phi + sin theta sin phi cos psi , y = cos theta sin phi - sin theta cos phi cos psi and z = sin theta sin psi , then x^(2) + y^(2) + z^(2) equals :

(3 cos phi+cos 3 phi)/(3 sin phi-sin 3 phi)=

If a sin phi+b cos phi=c then a cos phi-b sin phi is

If A=[[cos theta, sin theta],[sin theta, cos theta]],B=[[cos phi, sin phi],[sin phi, cos phi]] show that AB=BA.

If A=[[cos theta, sin theta],[sin theta, cos theta]],B=[[cos phi, sin phi],[sin phi, cos phi]] show that AB=BA.

If sin theta+ sin phi= a and cos theta+ cos phi= b , find : sin (theta+ phi) .

If sin theta+ sin phi= a and cos theta+ cos phi= b , find : cos (theta+ phi) .

If sin theta+ sin phi= a and cos theta+ cos phi= b , find : cos (theta- phi) .