# Trig Proof

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• April 9th 2010, 01:28 PM
sigma1
Trig Proof
i have been trying to crack this but i have had no luck. hope someone can help.

$(sin4x + sin2x)/(cos4x+cos2x) = tan3x$

the X varibale is actually (pie), i just could not type it into the window...
• April 9th 2010, 02:19 PM
Deadstar
Quote:

Originally Posted by sigma1
i have been trying to crack this but i have had no luck. hope someone can help.

$(sin4x + sin2x)/(cos4x+cos2x) = tan3x$

the X varibale is actually (pie), i just could not type it into the window...

What exactly are you trying to crack?

$\sin(n \pi) = 0$ for $n = \pm 1$, $\pm 2$, ...

$\tan(n \pi) = 0$ for $n = \pm 1$, $\pm 2$, ...

Hence both sides = 0.
• April 9th 2010, 02:23 PM
Deadstar
Oh yeah and the Latex for pi (not pie lol) is...

\pi $\pi$
• April 9th 2010, 04:32 PM
sigma1
the actual question is prove that

$
(sin4A + sin2A)/(cos4A+cos2A) = tan3A
$