okay this problem stumped me for a while but here is my work for it, and I just got stuck at the end so if any help can be provided thanks in advance.(adsbygoogle = window.adsbygoogle || []).push({});

sin3x = sinx

sin(2x + x) = sinx

sin2x cos x + cos2x sinx = sinx

2sinx cosx cosx + (2cos^2(x) -1) sinx = sinx

2sinx cos^2(x) + 2cos^2(x) sinx - sinx = sinx

2sinx cos^2(x) + 2cos^2(x) sinx - 2sinx = 0

2sinx (cos^2(x) + cos^2(x) - 2) = 0

2sinx (2cos^2(x) - 2) = 0

4sinx(cos^2(x) -1) = 0

4sinx(-sin^2(x)) = 0

4sinx = 0 , -sin^2x = 0

x = 0 , x = 0, pi, 2pi

Why is it when I graph the equation sin3x - sinx = 0 on my calculator, it comes with 7 solutions when i only have 3?

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# Homework Help: Sin3x = sinx Solve for x.

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