The Double Angle Formula (1 Viewer)

studentcheese · Mar 28, 2009

Need help with two problems.

1) Prove:

Note: sinA + cosA is not equal to zero.

2) Solve for

Thanks.

lyounamu · Mar 28, 2009

studentcheese said:
Need help with two problems.

1) Prove:

Note: sinA + cosA is not equal to zero.

2) Solve for

Thanks.

Both questions are wrong, they don't make sense.

studentcheese · Apr 4, 2009

Don't worry then. I figured out how to do it. I'll post the solution up for anyone who tried to do it. Thanks. $tanx - cotx = 1 - cot2x$
$tanx - \frac{1}{tanx}= 1 - \frac{1-tan^2x}{2tanx}$
$2tan^2x - 2 = 2tanx - 1 +tan^2x$
$tan^2x - 2tanx - 1 = 0$
$tanx =\frac{2 \pm\sqrt{ 8}}{2}$
$x = 67.5, 247.5$ or $x= 157.5, 337.5$

The Double Angle Formula (1 Viewer)

studentcheese

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lyounamu

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