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Solve the Equations

  • Thread starter Enochfoul
  • Start date
  • #1
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2

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

Answers and Replies

  • #2
epenguin
Homework Helper
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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°.
 
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  • #3
ehild
Homework Helper
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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.
 

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