Question

Find the values of -

cos 60° × cos 30° + sin 60° × sin 30°

Answer 1

cos 60° × cos 30° + sin 60° × sin 30°

= ${\displaystyle \frac{1}{2}\times \frac{\sqrt{3}}{2}+\frac{\sqrt{3}}{2}\times \frac{1}{2}}$

= ${\displaystyle \frac{\sqrt{3}}{4}+\frac{\sqrt{3}}{4}}$

= ${\displaystyle \frac{\sqrt{3}+\sqrt{3}}{4}}$

= ${\displaystyle \frac{2\sqrt{3}}{4}}$

= ${\displaystyle \frac{\sqrt{3}}{2}}$