Homework Statement
If r(t) = \left\langle\2e^{2t},4e^{-2t},te^{2t} \right\rangle, find r'(t) \cdot r''(t).
Homework Equations
r'(t) = \left\langle4e^{2t},-8e^{-2t},2te^{2t}+e^{2t} \right\rangle
r''(t) = \left\langle8e^{2t},16e^{2t},4te^{2t}+4e^{2t} \right\rangle
The Attempt at a Solution
r'(t)...