How to find a general solution

[chris99191]

1. Find the general solution to sin3x+sin2x=0


2. I am not sure what to use. I think the sin2x=2sinxcosx but I am unsure where to go from there


3. sin3x+2sinxcosx=0 unsure

 

[dextercioby]

Use this and remember this page for future problems with circular trigonometric functions.

http://en.wikipedia.org/wiki/Trigonometric_identity#Product-to-sum_and_sum-to-product_identities

 

[Metaleer]

Also, https://www.physicsforums.com/showthread.php?t=481844" addresses a similar a equation.

 

[chris99191]

This still doesn't help me understand sorry. I think we have to put them into the sin general solution formula but I am not sure how

 

[HallsofIvy]

I have no idea what you mean by "sin general solution formula" but what the others are referring to are that
$$\sin(2x)= 2\sin(x)\cos(x)$$
and
$$sin(3x)= 3\sin(x)cos^2(x)- \sin^3(x)$$
$$= 3sin(x)(1- \sin^2(x))- \sin^3(x)= 3\sin(x)- 4\sin^3(x)$$

You can write your equation in terms of sine and cosine only.