Solving Trig Equations: 4 More Solutions to Find

[kuahji]

The question is Solve the trig equation for all values of the variable in the first positive rotation.

Problem cos^2 3x = 1

Heres how I attempted to solve the equation

3x = arccos (1)^2

1/3 arccos 1

cos = 0 & 180

However, on the test, the professor stated there were 4 more solutions & I'm having trouble trying to figure them out. What more do I need to do?

 

[Päällikkö]

3x = arccos (1)^2

This is wrong.cos²(3x) = 1
<=> cos 3x = +- 1
Can you do the rest?

 

[kuahji]

Yes, thank you. I see what I did now & this helps.