Solve x^2sin(x)+2x(cosx)=0

[harriettey]

I've tried it so many times and now I'm just wasting paper.

Help me please.

Thank you.

 

[daon2]

I've tried it so many times and now I'm just wasting paper.

Help me please.

Thank you.

First thing is to mark zero as a solution, then divide through by x. Now you are looking at \(\displaystyle x\sin(x)+2\cos(x)=0\). This equation will have infinitely many solutions, any of which I believe need to be found numerically.

 

[Quaid]

Solve x^2 sin(x) + 2x cos(x) = 0

I've tried it so many times and now I'm just wasting paper.

Hi Harriett:

What did you try? Please show us.

(My first step would be: divide both sides by x)

Also, please read a summary of our posting guidelines HERE.

Cheers :cool:

 

[pka]

I've tried it so many times and now I'm just wasting paper.
Help me please.

You will not find an algebraic solution of this.
Factor it: \(\displaystyle x(x\sin(x)+2\cos(x))=0\). One solution is quite clear.
The other solutions require computing power. Look here.

 

[harriettey]

You will not find an algebraic solution of this.
Factor it: \(\displaystyle x(x\sin(x)+2\cos(x))=0\). One solution is quite clear.
The other solutions require computing power. Look here.

Thank you, I have already looked on Wolfram Alpha, and they are all valid solutions, but I don't understand how to compute them myself.

Could you help at all?

Thank you

H

 

[Quaid]

Do you have a graphing calculator?

You could plot the graphs of x*sin(x) and -2*cos(x), and then have the machine give you some intersection points. (There are infinite solutions.)