# Stuck in this trigonometric equation...

• May 17th 2011, 08:31 AM
klik11
Stuck in this trigonometric equation...
I need to get from this:
a^2 / 4*sin(x)*cos(x)

To this:
a^2 * tan(x)

thanks
• May 17th 2011, 08:35 AM
TheEmptySet
Quote:

Originally Posted by klik11
I need to get from this:
a^2 / 4*sin(x)*cos(x)

To this:
a^2 * tan(x)

thanks

That is not possible the statement is false!
• May 17th 2011, 08:38 AM
klik11
Is 2*a^2 / 4*sin(x)*cos(x)
false too?
• May 17th 2011, 08:41 AM
TheEmptySet
Quote:

Originally Posted by klik11
Is 2*a^2 / 4*sin(x)*cos(x)
false too?

Just so we are clear is this what you intended in the first post.

$\frac{a^2}{4\sin(x)\cos(x)}=a^2\tan(x)$

you 2nd question does not make sense. An expression cannot be true or false in the first part you wanted to show the above identity was true and it isn't.
• May 17th 2011, 09:23 AM
klik11
Yes you were right...
Last question for today:
can
a^2 * cos(2x) + a^2 / 2*sin(x)*cos(x)
be
a^2 * tan(x)
• May 17th 2011, 09:29 AM
TheEmptySet
Quote:

Originally Posted by klik11
Yes you were right...
Last question for today:
can
a^2 * cos(2x) + a^2 / 2*sin(x)*cos(x)
be
a^2 * tan(x)

Please use parenthesis do you mean

$\frac{a^2\cos(2x)+a^2}{2\sin(x)\cos(x)}$

or

$a^2\cos(2x)+\frac{a^2}{2\sin(x)\cos(x)}$
• May 17th 2011, 09:32 AM
klik11
the second one
• May 17th 2011, 09:44 AM
TheEmptySet
No what if

$x=\frac{\pi}{4}$

plug that into both equations and see what you get