I'm a Beaver, You're a Beaver, We are Beavers All

For those of you that don't read nerd, his t-shirt says "I'm a cutie pie"

I'm a Beaver, you're a beaver, we are beavers all;
And when we get together, we do the beaver call:
E to the u, du dx, E to the x dx
Cosine, secant, tangent, sine, 3.14159
Integral, radical, u dv
Slipstick, sliderule, MIT!