# Laplace's equation on a rectangle with mixed b.c.s

by sarideli18
Tags: equation, laplace, mixed, rectangle
 Math Emeritus Sci Advisor Thanks PF Gold P: 39,682 You need a function that has derivative 0 at y= 0 and value x at y= H. The first condition makes me think of a quadratic. Look at $v(x, y)= (x/H^2)y^2$. And then change your function to w(x,y)= u(x,y)- v(x,y).