/sci/ - Science & Math

[Anonymous No.3273678]

Hey guys,

I could use a little help here. This is not HW but for an undergrad research project I am working on. Besides, its better than half the threads on page0 anyway.

If I have the values of cos(x) and sin(x), then how do I use this to find e^x

I am finding that it has to do with this:
http://en.wikipedia.org/wiki/Hyperbolic_function#Relationship_to_the_exponential_function
But I don't have sinh(x) and cosh(x), I just have sin(x) and cos(x)

wat do?

[Anonymous No.3273697]

Taylor series expansion. Expand cosx, sinx, and e^x, and you'll find that:

<span class="math">e^{ix}=cosx+isinx[/spoiler]

[Anonymous No.3273706]

>>3273697
Thanks, but I can't do it that way.

That is the way I am currently doing it and I am trying to find a way to calculate it in an FPGA really fast. Taylor series is taking too long so I am trying another approach.

I know its possible to do it this way though. Sorry I should have specified before.

[Anonymous No.3273739]

Wolframalpha has "relation" command/function/whatever.
You should always try to start with wolframalpha.
http://www.wolframalpha.com/input/?i=relation+sin%28x%29*cos%28x%29+and+exp%28x%29
>I have the values of cos(x) and sin(x)
Are those values real or complex?

[Anonymous No.3273740]

<div class="math">e^x=cos(ix)-isin(ix)</div>

[Anonymous No.3273782]

arccos(cos(x)) = x
multiply by i

cos(ix) - isin(ix) = e^x