1 | initial version |

There are two comments in order here:

**A)** as you state yourself, the integrands of your expression, e.g.

```
U1*phi1[0]
y |--> (y - 1)*((y - 1)*(y + 1)*a12*y + (y - 1)*(y^2 + 1)*a13*y + (y - 1)*a11*y)*y
```

contains lots of symbolic varibles: `a12,a13,a11`

which *are* no valid floats, even after substituting a valid float for the integration variable y. That's what the error tells you ;-) . SciPy's quad has to know the numerical values of such parameters - how else could it do a numerical integral? How to supply *float* parameters to quad is described at http://docs.scipy.org/doc/scipy/reference/generated/scipy.integrate.quad.html#scipy.integrate.quad E.g.:

```
f(y,a12,a13,a11)=U1*phi1[0]
quad(f,0.0,1.0,args=(1,1,1,))
(0.1261904761904762, 1.4009957215507927e-15)
```

**B)** having said that, and not knowing what your actual problem is, I however presume that the preceeding is not what you actually want, and that rather you want to set up some kind of linear equation (eq1 ?) with symbolic variables and *numerically* evaluated 'constants'. If that is so, I would disect the numerical integration of each of those constant off from the symbolic part of the code.

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