Solve: 2sin theta - cos theta =0 for 0< or = theta < 2 Phi

S

SueC01

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Feb 16, 2009
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It is sad that I have spent my whole long weekend on this homework but it is what it is.

With that being said this is the last problem I am stuck on.

Solve: 2sin theta - cos theta =0 for 0< or = theta < 2 Phi

I have 0,phi/2,phi,3phi/2 :?


I have so many graphs that I don't remember which one I used.
I think I might have thrown it away without thinking.
Please show me which equation I should use.

Thank you,Sue
 
Re: My last trig problem for today!!

SueC01 said:
It is sad that I have spent my whole long weekend on this homework but it is what it is.

With that being said this is the last problem I am stuck on.

Solve: 2sin theta - cos theta =0 for 0< or = theta < 2 Phi

I have 0,phi/2,phi,3phi/2 :? <<<Incorrect - check your problem carefully for correctness

use the trig identity:

\(\displaystyle \tan(\theta) \, = \frac{\sin(\theta)}{\cos(\theta)}\)

As posted, you would need calculator to come up with exact measurement of the angle.

I have so many graphs that I don't remember which one I used.
I think I might have thrown it away without thinking.
Please show me which equation I should use.

Thank you,Sue
Click to expand...
 
Re: My last trig problem for today!!

OK. Let's see if I have it right this time:

Phi/3, Phi/2, 2Phi/3 and 3Phi/2

or

Phi/6, Phi/2, 5Phi/6,3Phi/2

Sometimes I really wonder what I am doing........ :( ,

Sue
 
Re: My last trig problem for today!!

SueC01 said:
OK. Let's see if I have it right this time:

Phi/3, Phi/2, 2Phi/3 and 3Phi/2 <<<< Incorrect

or

Phi/6, Phi/2, 5Phi/6,3Phi/2<<<< Incorrect - assuming your problem statement was correct

How did you get those - please show work if you need us to trace your mistake



Sometimes I really wonder what I am doing........ :( ,

Sue
Click to expand...
 
Ok. A classmate called a little while ago and we worked it out.

The answers we got were

0,Phi/6,5Phi/6,Phi

I pray this is right.

Sue
 
SueC01 said:
Ok. A classmate called a little while ago and we worked it out.

The answers we got were

0,Phi/6,5Phi/6,Phi <<< Incorrect

I pray this is right.

Sue
Click to expand...
 
He is just going to have to show us how to work it out,

Thank you for all you help.

I'll be back............. :D

Sue
 
Re: My last trig problem for today!!

[
Solve: 2sin theta - cos theta =0 for 0< or = theta < 2 Phi

\(\displaystyle \frac{\sin(\theta)}{\cos(\theta)} \, = \, \frac{1}{2}\)

\(\displaystyle \tan(\theta) \, = \, \frac{1}{2}\)

? = 26.56505118° and 206.56505118° <<< using calculator
 
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