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#### Kramer55

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I have a quick question, how would I simplify the following:

sin(pi + x) + sin(pi - x) ?

Thanks for any help

#### Big-K

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I forget that kind of thing at the moment, although I know trig functions fine. I tried substituting 5 for x, and came up with .1091. I see no use for this kind of number though, unless you were to use the reverse sine on it.

All numbers in the above statement are estimated. Then again, you said simplify.

#### barfly

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Multiply it out to get

sin pi + sin x +sin pi - sin x

= 2 sin pi

#### Big-K

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whoops, yeah go with that

#### colman77

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You can't distribute the sine function like that, i don't think. Somebody hasn't taken trig/pre-calc in a while.
sin(x-pi) = cos(x)
Can't remember what to do with sin(x+pi), but you can simplifiy it somehow. Anyway, you've probly learned it by now.

#### cheese

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Oh i cant wait until i have to do this..

#### Ratboy

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Kramer55,

sin(pi + x) + sin(pi - x)

sin(pi + x) = -sin(x)
sin(pi - x) = sin(x)

sin(pi + x) + sin(pi - x) = -sin(x) + sin(x) = 0

colman77,

You're thinking of: sin(pi/2-x) = cos(x)

#### colman77

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yes, I am! Oh well, it's not like my final is tomorrow or something. Oh, wait, it is. Crap.

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