[" 2.If "(sin alpha)/(a)=(cos alpha)/(b)," then "a sin2 alpha+b cos2 alpha=],[" A) "a],[" O) "a+b],[" (a) "b],[" (1) "(1)/(2b)]

If (sin alpha )/(a) = ( cos alpha )/(b) , then a sin 2alpha + b cos 2 alpha =

If sin alpha + cos alpha = b, then sin 2 alpha is equal to

If sin alpha + cos alpha = b then sin 2 alpha is equal to . . . . .

If A_(alpha), = [{:(cos alpha , sin alpha),(-sin alpha , cos alpha):}] , then

(sqrt2 - sin alpha - cos alpha )/( sin alpha - cos alpha)=

(sqrt2 - sin alpha - cos alpha )/( sin alpha - cos alpha)=

I : If (cos alpha )/(a)=(sin alpha )/(b) then a cos 2 alpha + b cos 2 alpha =a II : If (sin alpha )/(a) =(cos alpha )/(b) then a sin 2 alpha + b cos 2 alpha = a

(sin 5 alpha-sin3alpha)/(cos 5 alpha+2 cos 4 alpha+cos 3alpha)=