Question

The value of cos² 17° − sin² 73° is 

Options

•  1

• \[\frac{1}{3}\]

• 0

• -1

Answer 1

We have: 

`cos^2 17°-sin^2 73°`

= `cos^2(90°-73°)-sin^2 73°` 

=` sin^2 73°-sin^2 73°` 

= 0