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- Thread starter Miike012
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Deriving the rotation matricies.

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jhae2.718

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for instance... lets say we have two angles 30 and 45... you could either use the identity or just straight out solve for it...

not lets say we have two angles 1 and 45... you can not solve for this using the sum of two angles identity... HOWEVER you can solve this using algebra... and law of sines....

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jhae2.718

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For the sum/difference, formulas, as blather stated, they can be used to derive the rotational matrix in Euclidean space: http://planetmath.org/encyclopedia/DerivationOfRotationMatrixUsingPolarCoordinates.html [Broken]

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Alright.. well I have no idea what that is.. im only in trig... when will I get there?

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jhae2.718

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When you take calc, for another example, you'll find that [tex]\cos^2(\theta) = \frac{1+\cos(2\theta)}{2}[/tex] is useful for integrals. (You can't integrate cos^2 or sin^2, but you can transfrom them inot something linear and then solve it.)

Trig seems pointless when you just calculate the angles like that, but it's actually extremely useful.

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Lol yes I have some time before I take that class. lol

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Basic Complex Analysis

by Marsden

This book shows a lot of cool things about trig identities in one of the first two chapters. You are always free to go faster than your education.

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Thank you for the advise blather... I will also check out the book...

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