Trig

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Prove the following functions:

(sinx+sin2x)/(1+cosx+cos2x)=tan x
(cos3x/sinx)+(sin3x/cosx)=2cot2x
tan2x=(2/cotx-tanx)

theses are due in the am. Fastness would be great?

  • Trig -

    You can't prove a function. You can prove an identity.

    Using s for sinx, c for cosx, t for tanx, to make things look less cumbersome:

    (s+2sc)/(1+c+2c^2 - 1) = t
    (s+2sc)/(c + 2c^2) = t
    s(1+2c)/[c(1+2c)] = t
    s/c = t
    t = t

  • Trignometric math -

    tanx

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