b. Explain why the initial value problem y'=4xsqrt(1-y^2) with y(0) = 4 does not have a solution.
I already solved the differential equation and got y=sin(2x^2+C)
I don't know what to do from there
what you do is use the rest of the information they gave you: y(0)=4
So, you have to find C using
4 = sin(2*0+C)
Now, when does sin(θ) = 4? Never!