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anonymous
 5 years ago
sin 4x = 4 sin x cos³x4sin³x cos x. Show as an identity.
anonymous
 5 years ago
sin 4x = 4 sin x cos³x4sin³x cos x. Show as an identity.

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anonymous
 5 years ago
Best ResponseYou've already chosen the best response.02sin2xcos2x = 4sinxcosx(cos^2 x  sin^2 x)

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0skipped a few steps there , I see what you have done, but to someone asking the question it is unlikely they will be able to follow

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0i assume they know basic trig ratios

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Have difficulty doing these, could you help with the steps so I can try and understand

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0sin(2a) = 2sin(a)cos(x)

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0cos(2a) = cos^2 (a)  sin^2 (a)

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0now sin(4x) = sin( 2 * 2x) = 2sin(2x)cos(2x) by applying the first formula once

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0hard to memorize, I see those in my notes. Thanks for helping

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0now we can apply the first formula again to sin(2x) , to get 2sin(x)cos(x) and we apply the second formula to the cos(2x) term to get cos^2 (x)  sin^2 (x)

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0so sin(4x) = 2 * ( 2sin(x)cos(x) ) ( cos^2 (x)  sin^2(x) )

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0= 4sin(x)cos(x) ( cos^2(x)  sin^2(x)) , then expand
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