Euler's and improved Euler's method,...find the exact solution

1.         y'=1/2 -x + 2y            y(0) = 1
                       Find the exact solution "Sphee"
                        {0 with line diagonal of the 0}

2.   y'=x square + y square      
                               y(0)=1
          
a. Let h=.1 use Euler and improve to approximate to get
            Sphee(.1)  Sphee(.2)  Sphee(.3)
b. h=.05 so compare with Shee(.1)
        Sphee (.2)         sphee is a circle