Jika sin x = 1/5 ✓5 , maka cos x - 5 cos ( π/2 + x ) + 2 sin ( π - x ) adalah

sin x = (1/5)√5
cos x = (2/5)√5

cos x - 5.cos (π/2 + x) + 2.sin (π - x)
= cos x - 5.cos (90 + x) + 2.sin (180 - x)
= cos x - 5(-sin x) + 2.sin x
= cos x + 5.sin x + 2.sin x
= cos x + 7.sin x
= (2/5)√5 + 7(1/5)√5
= (9/5)√5