Cos (x+135) = sin x .nilai tanx adalah

jawab

cos(x + 135)= sin x
cos x cos 135 - sin x sin 135 = sin x
cos x (- 1/2 √2) - sin x (1/2√2) = sin x
- 1/2 √2  cos x - 1/2 √2 sin x = sin x
-1/2 √2 sin x - sin x = 1/2 √2 cos x
(-1/2 √2 -1) sin x = 1/2 √2 cos x
sin x / cos x =  (1/2 √2) / (-1/2 √2 -1)
tan x  =  1 - √2