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Edutopia
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question about the proof of trig addition formulas for cos:
 one year ago
 one year ago
Edutopia Group Title
question about the proof of trig addition formulas for cos:
 one year ago
 one year ago

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Edutopia Group TitleBest ResponseYou've already chosen the best response.0
sorry about the scrolling: http://en.wikipedia.org/wiki/Proofs_of_trigonometric_identities on the part with the diagram for trig addition formulas, where does "RPQ = (PI/2)  RPQ" come from?
 one year ago

Edutopia Group TitleBest ResponseYou've already chosen the best response.0
also any sites with a better, easy to understand, definition would be greatly appriciated
 one year ago

AccessDenied Group TitleBest ResponseYou've already chosen the best response.1
RPQ = pi/2  RQP pi/2 radians is 90 degrees. RPQ = 90 degrees  RQP which we can see because that triangle is a right triangle, so the other two angles have to be complementary to add up to 180 degrees interior.
 one year ago

Edutopia Group TitleBest ResponseYou've already chosen the best response.0
but PRQ is only one of the complementary angles, how do i know that it is half of 90?
 one year ago

AccessDenied Group TitleBest ResponseYou've already chosen the best response.1
I believe PRQ is meant to be a right angle, 90 degrees or pi/2 radians, although it doesn't appear to be indicated as such...
 one year ago

AccessDenied Group TitleBest ResponseYou've already chosen the best response.1
dw:1357875756276:dw Just drawing diagram here
 one year ago

Edutopia Group TitleBest ResponseYou've already chosen the best response.0
im sorry we got it switched around somewhere its RPQ not PQR
 one year ago

Edutopia Group TitleBest ResponseYou've already chosen the best response.0
they are proving that RPQ=alpha
 one year ago

AccessDenied Group TitleBest ResponseYou've already chosen the best response.1
Since PRQ is a right triangle with right angle PRQ, RPQ and RQP are complementary. <RPQ + <RQP + <PRQ = 180 <RPQ + <RQP + 90 = 180 <RPQ + <RQP = 90 <RPQ = 90  <RQP Would that make sense?
 one year ago

Edutopia Group TitleBest ResponseYou've already chosen the best response.0
OH RPQ is a TRIANGLE! oops
 one year ago

AccessDenied Group TitleBest ResponseYou've already chosen the best response.1
the pi/2 is just radians, i was using degrees. sorry if that is confusing...
 one year ago

Edutopia Group TitleBest ResponseYou've already chosen the best response.0
no its not i understand radians
 one year ago

AccessDenied Group TitleBest ResponseYou've already chosen the best response.1
Ah, okay. :)
 one year ago

Edutopia Group TitleBest ResponseYou've already chosen the best response.0
aha i see it, thank you very much!
 one year ago

AccessDenied Group TitleBest ResponseYou've already chosen the best response.1
You're welcome! :)
 one year ago
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