Jika tan x = 0,75 dan x di kuadran pertama, hitung nilai cos 2x
Matematika
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Pertanyaan
Jika tan x = 0,75 dan x di kuadran pertama, hitung nilai cos 2x
1 Jawaban
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1. Jawaban Anonyme
tan x = 0,75 = 3/4
r = √(3² + 4²) = 5
cos 2x
= 2cos² x - 1
= 2(4/r)² - 1
= 2(4/5)² - 1
= 32/25 - 25/25
= 7/25