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DLS
 2 years ago
cos36?
DLS
 2 years ago
cos36?

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hartnn
 2 years ago
Best ResponseYou've already chosen the best response.1first can u find sin 18 without calcy ?

hartnn
 2 years ago
Best ResponseYou've already chosen the best response.1let x= 18 5x = 90 3x = 902x now take sin on both sides.

hartnn
 2 years ago
Best ResponseYou've already chosen the best response.1sin 3x = sin(902x) sin 3x = cos 2x

hartnn
 2 years ago
Best ResponseYou've already chosen the best response.1now put the formula fo sin 3x and cos 2x in terms of powers of sin x only.

hartnn
 2 years ago
Best ResponseYou've already chosen the best response.1u get a cubic in sin x. solve it.

DLS
 2 years ago
Best ResponseYou've already chosen the best response.1wait,theres a formula for sin3x? :P

hartnn
 2 years ago
Best ResponseYou've already chosen the best response.1sin 3x = 3sin x  4 sin^3 x

DLS
 2 years ago
Best ResponseYou've already chosen the best response.1okay I guess i can do it now

hartnn
 2 years ago
Best ResponseYou've already chosen the best response.1from sin 18, u get cos 36 from the formula of cos 2x in terms of sin x
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