Question

How do you find the exact value of `sec120`?

Answer 1

`sec120^@=-2`

Explanation:

Using the `color(blue)"trigonometric identity"`

`color(red)(bar(ul(|color(white)(2/2)color(black)(sectheta=1/costheta;costheta≠0)color(white)(2/2)|)))`

`rArrsec120^@=1/cos120^@`

`"now "cos120^@=-cos60^@=-1/2`

`rArrsec120^@=1/(-1/2)=-2`