# Math Help - Differential Equation help?

1. ## Differential Equation help?

I have this question: I actually got -2.9 though, not -3.2. :/ To get this I found that separated dy/dx=xcosx^2 is y=c+((sin(x^2)/2) So when I put (0,-3) into that I get that c=-3. So then when I plug pi in for x I get that (sin(9.8)/2)-3= -2.9 ..What am I doing wrong here? :/ Thanks!

2. ## Re: Differential Equation help?

I don't know what you're doing wrong. Your reasoning is correct. (a) is the correct answer.

I get that $\dfrac{\sin(9.8)}{2}-3=-3.18324$ which isn't the correct answer but it's not far off.

Truncating $\pi^2$ to 9.8 so early isn't the best thing you could do.

3. ## Re: Differential Equation help?

I get $\frac{\sin{\pi^2}}{2}-3 = -3.215$.

- Hollywood

4. ## Re: Differential Equation help?

Thank you both!