jika tan x = a maka cos 2x =
Matematika
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Pertanyaan
jika tan x = a maka cos 2x =
1 Jawaban
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1. Jawaban luckysantoovpqyf
tan x = y / x
maka tan x = a / 1 (a = y, x = 1) r = akar (a^2 + 1)cos x = x / r = 1 / akar (a^2 + 1)
maka cos 2x = 2 cos^2 x - 1
= 2 * (1^2 / akar (a^2 + 1) ^ 2) - 1
= 2 * 1 / a^2 + 1 -1
=2 / (a^2 + 1) - a^2 + 1 / (a^2 + 1)
= 2 - a^2 + 1 / (a^2 + 1 ) = 3 - a^2 / (A^2 + 1)