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kaisan
 3 years ago
verify: sin(x+y)sin(xy)=2cosxsiny
kaisan
 3 years ago
verify: sin(x+y)sin(xy)=2cosxsiny

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malexander
 3 years ago
Best ResponseYou've already chosen the best response.0cos(x+y)=cosxacosysinxsiny cos(xy)=cosxcosy+sinxsiny addition produces 2cosxcosy

lgbasallote
 3 years ago
Best ResponseYou've already chosen the best response.1take the left hand side...do you know the formula for sin(x+y) and sin(xy)?

kaisan
 3 years ago
Best ResponseYou've already chosen the best response.0i think so but i'm not sure

lgbasallote
 3 years ago
Best ResponseYou've already chosen the best response.1sin(x+y) = sinxcosy + sinycosx sin(xy) = sinxcosy  sinycosx can you do it from here?

kaisan
 3 years ago
Best ResponseYou've already chosen the best response.0it looks familiar but i can't figure it out. is it one of the cosine identities?

lgbasallote
 3 years ago
Best ResponseYou've already chosen the best response.1no...you substitute those into your problem sin(x+y)  sin (xy) = sinxcosy + cosxsiny  (sinxcosy  cosxsiny)

kaisan
 3 years ago
Best ResponseYou've already chosen the best response.0how to do all of this in general

lgbasallote
 3 years ago
Best ResponseYou've already chosen the best response.1basically you memorize the identities...

lgbasallote
 3 years ago
Best ResponseYou've already chosen the best response.1i did not do anything fancy...all i did was substitute identities

lgbasallote
 3 years ago
Best ResponseYou've already chosen the best response.1so regarding this problem...you're good?

lgbasallote
 3 years ago
Best ResponseYou've already chosen the best response.1sinxcosy + cosxsiny  (sinxcosy  cosxsiny) sinxcosy = cosxsiny  sinxcosy + cosxsiny

lgbasallote
 3 years ago
Best ResponseYou've already chosen the best response.1that's a + not an =

kaisan
 3 years ago
Best ResponseYou've already chosen the best response.0i don't understand what you did

lgbasallote
 3 years ago
Best ResponseYou've already chosen the best response.1i distributed the minus sign

lgbasallote
 3 years ago
Best ResponseYou've already chosen the best response.1so you're good now?
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