To solve 5sin(2x)=3cosx
you should rewrite it as?

Question

To solve 5sin(2x)=3cosx
you should rewrite it as?

sweetburger · Answer

I think you can substitute sin(2x) for 2sin(x)cos(x) then you have 10sin(x)cos(x) = 3 cos(x)

sweetburger · Answer

from there you can do this 10sin(x)cos(x) - 3cos(x) = 0 Now bring together like terms.

cutiecomittee123 · Answer

I think that works

sweetburger · Answer

I wrote that wrong factor out like terms*

smilie2015 · Answer

by using half angle formula it will be answer B

cutiecomittee123 · Answer

5sinx+3cosx=0?

cutiecomittee123 · Answer

@smilie2015

sweetburger · Answer

I ended up at cosx(10sinx - 3) = 0

cutiecomittee123 · Answer

Yeah that is a valid answer because its on the choices

mathmale · Answer

Please go back to the original question posted by cutie.  Note that there is a trig identity for the double angle sine formula:  sin 2x = 2 sin x cos x.

Use this identity in the given equation.  Figure out how to solve this.  Note that there will be more than one solution.

mathmale · Answer

Note:  In the long run, you are trying to solve for x (which is an angle).  But this question only asks you to re-write the given equation to make this solution easier.

mathmale · Answer

@sweetburger :  You were right all along, from your very first response.  :)

cutiecomittee123 · Answer

okay I got it, thanks guys!