What Identity should I use to solve this.

$\displaystyle csc x-\frac{cotx}{secx} =sinx$

Printable View

- Mar 7th 2010, 04:17 PMmtt0216What identity should I use?
What Identity should I use to solve this.

$\displaystyle csc x-\frac{cotx}{secx} =sinx$ - Mar 7th 2010, 04:20 PMmr fantastic
- Mar 8th 2010, 10:46 AMmtt0216
I meant to say prove sorry about that.

The problem I have with this problem is that I don't know how to change

$\displaystyle \frac{cotx}{secx}$ into a different form.

Its just the fact thats its in an equation and I just don't know where to start. - Mar 8th 2010, 10:54 AMmr fantastic
- Mar 8th 2010, 11:17 AMmtt0216
I know the definitions:

csc x = 1/sinx

sec x = 1/cosx

Cot= cosx/sinx

But once I put them into the equation I dont know what to do. - Mar 8th 2010, 11:20 AMmr fantastic
- Mar 8th 2010, 11:27 AMmtt0216
- Mar 8th 2010, 11:42 AMbigwave
as already mentioned...

$\displaystyle

\frac{1}{\sin{\theta}}

-\frac

{\frac{\cos{\theta}}{\sin{\theta}}}

{\frac{1}{\cos{\theta}}}

\rightarrow

\frac{1}{\sin{\theta}}-\frac{\cos{\theta}}{\sin{\theta}}

\frac{\cos{\theta}}{1}

\rightarrow

\frac{1-\cos^2{\theta}}{\sin{\theta}}

\rightarrow

\frac{\sin^2{\theta}}{\sin{\theta}}= \sin{\theta}

$

EDIT(Cool)probably already got this - Mar 8th 2010, 11:55 AMmtt0216
Yea thats what I had. thanks