Trig Identities (2 Viewers)

Shazer2

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Hey guys, trig identities are probably my biggest downfall when it comes to trigonometry and I am up to the final question for trig identities in my textbook, but I don't know how to approach it. So I was hoping I could get some help and also some advice on how you would usually approach a trig identity question.

 
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Hey guys, trig identities are probably my biggest downfall when it comes to trigonometry and I am up to the final question for trig identities in my textbook, but I don't know how to approach it. So I was hoping I could get some help and also some advice on how you would usually approach a trig identity question.

use the LHS and expand it ?
 

HSC2014

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Just expand both sides and you will see that they are equal
 
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I got it, expand LHS; u get sin beta

then expand RHS; u get sin beta

therefore LHS=RHS :)
 

enoilgam

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Hey guys, trig identities are probably my biggest downfall when it comes to trigonometry and I am up to the final question for trig identities in my textbook, but I don't know how to approach it. So I was hoping I could get some help and also some advice on how you would usually approach a trig identity question.

I loved this stuff (still do). Just a tip, manipulate the identities into sin and cos values, then solve from there.

I can write and scan a proof if you want (can't latex).
 

Shazer2

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I loved this stuff (still do). Just a tip, manipulate the identities into sin and cos values, then solve from there.

I can write and scan a proof if you want (can't latex).
I'm not sure how to manipulate it, that's the problem. :)
 

HSC2014

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I understand all that, except for the second last line on the RHS. You go from to
x^2 + y^2 = r^2 (circle formula)

divide everything by r^2

x^2/r^2 + y^2/r^2 = 1

cos^2B + sin^2B = 1
 

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