1. Tardigrade
  2. Question
  3. Mathematics
  4. The value of Cos (270° +θ )Cos (90° - θ ) - Sin (270° - θ )Cos θ is

Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. The value of $Cos (270^\circ +\theta )Cos (90^\circ - \theta ) - Sin (270^\circ - \theta )Cos \theta$ is

KCETKCET 2005

Solution:

$\cos \left(270^{\circ}+\theta\right) \cos \left(90^{\circ}-\theta\right)$
$-\sin \left(270^{\circ}-\theta\right) \cos \theta$
$=\sin \theta \cdot \sin \theta+\cos \theta \cdot \cos \theta$
$=\sin ^{2} \theta+\cos ^{2} \theta=1$