Suppose r(t) = cos(t) i + sin(t) j+ 2tk represents the position of a particle on a helix, where z is the height of the particle. (a) What is t when the particle has height 6? t = (b) What is the velocity of the particle when its height is 6? v = (c) When the particle has height 6, it leaves the helix and moves along the tangent line at the constant velocity found in part (b). Find a vector equation for the position of the particle (in terms of the original parameter t) as it moves along this tangent line. L(t) =