I need help with this one... sin^{3}A+cos^{3}A/sinA + CosA = 1-sinAcosA Thanks
Last edited by WhatthePatel; Nov 10th 2012 at 03:24 PM.
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Originally Posted by WhatthePatel I need help with this one... sin^{3}A+cos^{3}A/sinA + CosA = 1-sinAcosA Hint: $\displaystyle x^3+y^3=(x+y)(x^2-xy+y^2)$
New identity? sin3x = 3cos^{2}xsinx-sin^{3}x
$\displaystyle \sin(3x) = \sin(2x+x) = \sin(2x)\cos(x) + \cos(2x)\sin(x)$ finish it using appropriate double angle identities. ... and, start a new thread for a new problem.
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