Solve the Equations

Homework Statement

Hi Could somebody please check my working to see if I have solved the following equations properly?

Homework Equations

1) cos2θ = sin θ
2) sin 2θ - 1 = cos2θ

The Attempt at a Solution

Scanned working attached

Attachments

• 4part1.pdf
1.4 MB · Views: 130
• 4part2.pdf
1.5 MB · Views: 127

epenguin
Homework Helper
Gold Member
Looked okay to me on quick look.

It is easy for you to check whether the results are correct! Just see if they work.

It is pretty obvious they are the only solutions. But if there were ever any doubt in a problem like this, you need only do a graph from 0 to 360°.

Enochfoul
ehild
Homework Helper

Homework Statement

Hi Could somebody please check my working to see if I have solved the following equations properly?

Homework Equations

1) cos2θ = sin θ
2) sin 2θ - 1 = cos2θ

The Attempt at a Solution

Scanned working attached
Check if all your results are solutions.
It would have been easier to substitute cos(2θ) with 2cos2(θ)-1.