Erwin Harahap

do Now or Never

Jika sin (x+30°) = sin x, buktikan tan x = 2 + √3 !

Posted by Erwin on October 11, 2015

sin (x+30) = sin x
sin x . cos 30 + cos x . sin 30 = sin x
sin x . (1/2)√3 + cos x . (1/2) = sin x

sin x – [ sin x . (1/2)√3 ] = cos x . (1/2)
sin x . [ 1 – (1/2)√3 ] = cos x . (1/2)
sin x / cos x = (1/2) / [1 – (1/2)√3]

tan x = 1 / (2 – √3)
*gunakan metode rasionalisasi penyebut. Diperoleh:
tan x = 2 + √3

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