Question

Sin (270-theta)sin (90-theta)-cos (90+theta)

Answer 1

$\sin(270 - \theta) \sin(90 - \theta ) - \cos(90 + \theta) \\ = (- \cos \theta )\cos\theta - ( - \sin\theta ) \\ = \sin\theta - \cos^{2} \theta$
hope this helps and..........