Question

Question #ac9a0

Answer 1

Convert to cos and verify

Explanation:

`sec(\pi+x) = 1/(cos(\pi+x))`

`= 1/(cos\pi cosx-sin\pi sinx)`

`cos \pi = -1, sin \pi = 0 \implies`
`sec(\pi+x) = 1/(cosx\times -1 - \cancel(0 \times sin x))`
`sec(pi+x) = -secx`