Prove

Asked by  | 17th Sep, 2008, 07:17: PM

Expert Answer:

tan(a+b) = (tana+tanb) / (1-tana tanb)

tan(a-b) = (tana-tanb) / (1+tana tanb)

so tan(π/4 + θ) + tan(π/4 - θ) = (1+tan θ) /(1-tan θ)   + (1-tan θ) / (1+tan θ)

= (1+tan θ)2 +(1-tan θ)2 / (1-tan2θ)

=2(1+tan2θ)/ (1-tan2θ) = 2/cos2θ =2sec2θ

Answered by  | 18th Sep, 2008, 01:02: PM

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