A potential energy function for a two-dimensional force is the form `U=3x^2y-7x`. Find the force that acts at the point `(x,y)`.

Explanation

To find the force that acts at the point \((x,y)\) given the potential energy function \(U = 3x^2y - 7x\), we will use the relationship between force and potential energy in two dimensions. The force components can be derived from the potential energy function by taking partial derivatives.

### Step-by-Step Solution:

1. **Understand the relationship between force and potential energy**:
The force \(\mathbf{F}\) in two dimensions can be expressed as:
\[
\mathbf{F} = -\nabla U
...