- #1

- 1,796

- 53

## Main Question or Discussion Point

Hi,

I'd like to solve a DE, create a function with the solution, then use that solution in a Piecewise function, and then NIntegrate the Piecewise function but I can't get NIntegate to work. Here's what I'm trying to do:

NIntegrate then tells me it's not numeric in the interval.

Can someone explain to me what I'm doing wrong?

Thanks,

Jack

I'd like to solve a DE, create a function with the solution, then use that solution in a Piecewise function, and then NIntegrate the Piecewise function but I can't get NIntegate to work. Here's what I'm trying to do:

Code:

```
mysol = NDSolve[{y'[x] == x, y[0] == 1}, y, {x, 0, 1}]
myy[x_] := Evaluate[y[x] /. mysol];
myf[x_] := Piecewise[{{myy[x], 0 < x <= 1}, {x^2, x > 1}}];
NIntegrate[myf[x], {x, 0, 2}]
```

Can someone explain to me what I'm doing wrong?

Thanks,

Jack