Diketahui tan x = p, maka cos 2x =
Matematika
srir0896
Pertanyaan
Diketahui tan x = p, maka cos 2x =
1 Jawaban
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1. Jawaban arsetpopeye
tan x = p = p/1 = de/sa => mi = √(p^2 + 1^2) = √(p^2 + 1)
sin x = de/mi = p/√(p^2 + 1)
cos x = sa/mi = 1/√(p^2 + 1)
Cos 2x = (cos x)^2 - (sin x)^2
= 1/(p^2 + 1) - p^2/(p^2 + 1)
= (1 - p^2)/(p^2 + 1)
= (1 - p^2)/(1 + p^2)