Question

I need the answer to #3, I’ve worked everything out and I don’t need an explanation, just the answer. Thanks

Answer 1

`7\sec ^2-7=0`

Divide both sides by 7:

`\sec ^2(x)-1=0`

Add 1 to both sides:

`\sec ^2=1`

Express sec(x) as 1/cos(x):

`\begin{gathered} (1)/(\cos ^2(x))=1 \\ \cos ^2(x)=1 \\ x=\pi n_{\text{ }};_{\text{ }}n\in\Z \end{gathered}`

Since the solutions are for the interval:

`\lbrack0,2\pi)`

The solutions are:

`x=0,\pi`