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# trig help

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# trig help

01-26-08, 04:30 PM
#1
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trig help

omg. I take 8 months off college to work a co-op and I've forgotten everything I've ever learned. Please help me. I feel like such a moron, but I've been trying to figure this out for a long time now.

I'm supposed to convert an equation in the form of y=cos(at+b) into the form of RE{Be^(jwt)}.
I get how to do that part. The problem is that I can't for the life of me figure out how to combine the real parts of the equation into one cosine function. It's in this form:

Acos(bt+c) + sin(bt)

I know I need to get it all into cosine, but I dunno how..? I know I'm going to feel stupid when I figure it out, but I've spent way too long on this already..
Thanks.
01-26-08, 04:42 PM
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Taerom
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Math with letters?! AAAHHHH!! *head explodes*
01-26-08, 05:22 PM
#3
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Originally Posted by Taerom
Math with letters?! AAAHHHH!! *head explodes*
This post matches said avatar perfectly
01-26-08, 05:47 PM
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supton
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I think you're looking for Euler's identity:
https://en.wikipedia.org/wiki/Euler's_identity
01-26-08, 07:54 PM
#5
RonH
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Chebyshev's cube root looks pretty confusing.

My son calls me about once a month needing help with college algebra. Now he's starting calculus. I tell him it's been toooooo many years since I've used or studied that stuff. Then I send him to Wikipedia.
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