2021-04-26
Vector math practice, especially the dot product.
- Find the intersection $(x,y)$ of the line $p(t) = (1,2) + t(2,-4)$ with the line $q(t) = (3,1) + t(-5,1)$.
- Find an equation of the line perpendicular to $$r(t) = (0,3) + t(2,2)$$ which passes through the point $(1,2)$.
- Find a real number u so that the dot product of $(3,4)$ with $(-2,5) + u(1,1)$ is zero.