I'm doing revision for school but I'm stuck on this question. I can't figure it out at all. I think it has something to do with trigonometric identities. Maybe someone else will know what to do?
Prove that (cotθcosθ)/(cotθ+cosθ) = (cosθ)/(1+sinθ)
Thanks!
Prove that (cotθcosθ)/(cotθ+cosθ) = (cosθ)/(1+sinθ)
Thanks!
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(cotθcosθ)/(cotθ+cosc) = ((cosθ/sinθ)*cosθ) / (cosθ/sinθ+cosθ)
=> [cos^2θ/sinθ] / [(cosθ + cosθ*sinθ)/sinθ)]
next you cancel out sinθ,
=> cos^2θ / (cosθ + cosθ*sinθ)
then you further cancel cosθ
=> cosθ / (1 + sinθ)
=> [cos^2θ/sinθ] / [(cosθ + cosθ*sinθ)/sinθ)]
next you cancel out sinθ,
=> cos^2θ / (cosθ + cosθ*sinθ)
then you further cancel cosθ
=> cosθ / (1 + sinθ)
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Factor out cotθ is way simpler.
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(cotθcosθ)/(cotθ+cosθ) = (cosθ)/(1+sinθ)
L.H.S. = (cotθcosθ)/(cotθ+cosθ)
L.H.S. = [cosθ*cosθ/sinθ] / (cosθ/sinθ + cosθ)
L.H.S. = [(cosθ)^2 / sinθ] / [cosθ(1+sinθ)/sinθ]
L.H.S. = cosθ / (1 + sinθ) = R.H.S. >=========< Q . E . D.
L.H.S. = (cotθcosθ)/(cotθ+cosθ)
L.H.S. = [cosθ*cosθ/sinθ] / (cosθ/sinθ + cosθ)
L.H.S. = [(cosθ)^2 / sinθ] / [cosθ(1+sinθ)/sinθ]
L.H.S. = cosθ / (1 + sinθ) = R.H.S. >=========< Q . E . D.
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x = (cotθcosθ) / cosθ+cotθ
1/x = cosθ+cotθ / cosθcotθ
1/x = cosθ/cosθcotθ + cotθ/cosθcotθ
1/x = 1/cosθ + 1/cotθ
1/x = 1/cosθ + sinθ/cosθ
1/x = 1+sinθ / cosθ
x = cosθ/(1+sinθ)
1/x = cosθ+cotθ / cosθcotθ
1/x = cosθ/cosθcotθ + cotθ/cosθcotθ
1/x = 1/cosθ + 1/cotθ
1/x = 1/cosθ + sinθ/cosθ
1/x = 1+sinθ / cosθ
x = cosθ/(1+sinθ)
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(cotθcosθ)/(cotθ+cosθ)
= (cotθcosθ)/(cotθ(1+sinθ))
= (cosθ)/(1+sinθ)
= (cotθcosθ)/(cotθ(1+sinθ))
= (cosθ)/(1+sinθ)
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And is supposed to mean something to us?