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#1

$Old$ January 13th, 2009, 06:46 PM

shanzwhaat $shanzwhaat is offline$

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$Default$ trig

$sec^2x * tanx = 2tanx$
in [0, 360) interval
find degree of x

Do I subtract 2tanx then use tan^2+1 = sec?

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#2

$Old$ January 13th, 2009, 06:55 PM

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$\frac{sin(x)}{cos^3(x)}= 2\frac{sin(x)}{cos(x)}$
$\frac{1}{2} = cos^2(x)$
$\pm \sqrt{\frac{1}{2}} = cos(x)$
Can you find the answer now?

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#3

$Old$ January 13th, 2009, 07:01 PM

shanzwhaat $shanzwhaat is offline$

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Yes, thanks.. but i did it like this and it worked....
$sec^2x * tanx = 2tanx$
and i divided tanx from the both sides and got..
$tan^2x+1=2$ then..
$tan^2x=1$ and finally..
$tanx=+/-1$

That way can work too right?

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#4

$Old$ January 13th, 2009, 07:04 PM

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Of course it is even better. I have a tendency to complicate things.

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#5

$Old$ January 13th, 2009, 07:05 PM

shanzwhaat $shanzwhaat is offline$

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Hhaha okay.. thank you so much for your help, it actually helped me to get to that step haha.

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