I am relatively new to mathematica and I need for a course to calculate the following derivative.
$\dfrac{\partial \int_{L(\alpha,u)} f(x,y,t) d(x,y)}{\partial t}$ with $L(\alpha,u) = \{ (x,y) | x cos(\alpha) + y sin(\alpha) = u \}$ for $\alpha \in [0,\pi[$ and $u \in \mathbb{R}$ for a certain function $f(x,y,t)$.
The problem is that I don't know how to set the condition $x cos(\alpha) + y sin(\alpha) = u$ in an integral.
Can someone help me with this?
Thanks in advance
Koen
