The tangent line to a smooth curve r t f t i g t j h t k at t to is the line that passes through the point f to 9 to h to parallel to v to the curve s velocity vector at to Use r to and r to to find parametric equations for the line that is tangent to the given curve at the given parameter value t to r t 4 sin t i t 6 cos t j 4e4t k to 0 What is the standard parametrization for the tangent line x 0 Z 4 Type expressions using t as the variable