Solve the following equation, giving the exact solutions which lie in [0, 2π). (Enter your answers as a comma-separated list.)
sin(2x) = sin(x)

Question

Solve the following equation, giving the exact solutions which lie in [0, 2π). (Enter your answers as a comma-separated list.)
sin(2x) = sin(x)

anonymous · Answer

I thought the answers were$$ x=0,\pi/3,5\pi/3 $$

anonymous · Answer

I'm getting cos(x) = 1/2.

anonymous · Answer

your dividing when you should subtract and factor.

anonymous · Answer

2sinxcosx-sinx=0-->
sinx(2cosx-1)=0

anonymous · Answer

Why would you do that?

anonymous · Answer

because if you divide then you are losing x=0 which works.

anonymous · Answer

Ah, true. Then it looks like you did everything fine then.

anonymous · Answer

but i am getting incorrect.

anonymous · Answer

Might it be how you're entering your solution? Maybe leave out the "x=" part and just put the list of numbers.

anonymous · Answer

i did that originally

anonymous · Answer

becuase there is and "x=" in front of the box.

anonymous · Answer

Hmm, all those solutions work, they are in the correct interval...

anonymous · Answer

Oh, we're missing π!

anonymous · Answer

jinks

anonymous · Answer

i thought that at the same time

anonymous · Answer

lol

anonymous · Answer

sin(2π)=sin(π)=0.
Gah, I feel even more embarrassed than I did before.

anonymous · Answer

It's been too long since I've done the trig.

anonymous · Answer

thanks a bunch! I appreciate it. We had a brainstorm going and it was good.

anonymous · Answer

Have a great weekend!