asked 84.1k views
3 votes
Solve sin2x + 4sin x + 3 = 0

asked
User JLavoie
by
8.8k points

1 Answer

2 votes
sin² x + 4 sin x + 3 = 0
Substitution: u = sin x
u² + 4 u + 3 = 0
u² + 3 u + u + 3 = 0
u ( u + 3 ) + ( u + 3 ) = 0
( u + 3 ) ( u + 1 ) = 0
u = - 3, u = - 1;
sin x = - 3 ( false )
sin x = - 1
Answer:
x = 3 π / 2 + 2 k π , k ∈ Z
answered
User Nopens
by
8.1k points
Welcome to Qamnty — a place to ask, share, and grow together. Join our community and get real answers from real people.