Question

I need some help, this is a trig question and I have no idea how to even start it.

Answer 1

Set your calculator to Degree mode.

`\alpha = {cos}^( - 1) (7)/(8)`

`\cos(2 \alpha ) = (7)/(x)`

`\cos(2 {cos}^( - 1) (7)/(8) ) = 2 {cos}^(2) ( {cos}^( - 1) (7)/(8) ) - 1 = (7)/(x)`

`2( { (7)/(8)) }^(2) - 1 = (7)/(x)`

`(17)/(32) = (7)/(x)`

`17x = 224`

`x = (224)/(17) = 13.176`

`\alpha = {cos}^( - 1) (7)/(8) = 28.955 \: degrees`

So x = 224/17 = 13.176 and theta = 28.955°.