Question

The question is in the image. Answer the question 25.

Answer 1

The Solution to Question 25:

Given:

`sec135^o`

We are required to evaluate the given expression.

`sec135^o=(1)/(\cos135^o)`

Recall:

`\cos135^o=-\cos(180-135)=-\cos45^o=-(√(2))/(2)`

Thus,

`sec135^o=(1)/(cos135^o)=(1)/(-(1)/(√(2)))=-(√(2))/(1)=-√(2)`

Therefore, the correct answer is:

`-√(2)`