Question

find the value of cosA(90–A)–sinA.sin(90–A)

Answer 1

it value will be cosa,(90-a)= Sina....Nd sin(90-a)=Cosa......then after substitute the value....we will got........sina-sina.cosa=sina(1-cosa)..

Answer 2

=Cos (90-A)- sinA . sin (90-A)
= Sin A - SinA . Cos A
= 0. CosA
= 0