Question

Tolong dong no. 8 beserta jalannya ya.. makasih..

Answer 1

Tan x = P/Q = de/sa
mi = √(P^2 + Q^2)
Sin 2x = 2 sin x cos x
= 2 . P/√(P^2 + Q^2) . Q/√(P^2 + Q^2)
= 2PQ/(P^2 + Q^2)

Cos 2x = (cos x)^2 - (sin x)^2
= (Q/√(P^2 + Q^2))^2 - (P/√(P^2 + Q^2))^2
= (Q^2 - P^2)/(P^2 + Q^2)

P cos 2x + Q sin 2x
= P(Q^2 - P^2)/(P^2 + Q^2) + Q(2PQ)/(P^2 + Q^2)
= (PQ^2 - P^3 + 2PQ^2)/(P^2 + Q^2)
= (3PQ^2 - P^3)/(P^2 + Q^2)
= P(3Q^2 - P^2)/(P^2 + Q^2) ..... E