Pretty easy I think but I was out sick when they did it in school and none of the trigonometric examples in my book cover this:
How does sin 2 a = 2sinacosa
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Pretty easy I think but I was out sick when they did it in school and none of the trigonometric examples in my book cover this:
How does sin 2 a = 2sinacosa
what do you mean. what values of a satisfy(all of them) or a proof of the identity (use sin(x+y) = sinxcox + sinycosy)
Its a double angle identity. This is my only idea of how to prove it involves a sum to product function but I keep on running into dead ends.
maybe
2sin(a)cos(a)
2(1/2(sin(a+a)+sin(a-a))): product to sum formula
sin(2a)+sin(0)
sin(2a)+0
sin(2a)
thats the closest I can get
sin(x+x) = sinxcox + sinxcox = 2sinxcosx = sin(2x)
also i mistyped the identity in my first post its sinxcosy + cosxsiny
It's a proof of identity question.
That looks right but it also looks way too simple to be the answer. Is there a way we can throw the sin rule/cosine rule/angle formula in the middle to prove of or something?Quote:
Originally Posted by God
so lord, do I just not exist or something
Why do you want it to be complex, Lord? It has a very simple answer, that is the elegance of Math.
Everytime I see this thread I read it as Meths help