the speed depends on t ... for what time, t = ? , did the problem want you to calculate the speed?
ok so the veloctiy is:
v(t) = (-2sint)i + (3cost)j +4k
so to find the speed you do
squareroot((-2sint)^2 + (3cost)^2 +(4k)^2)
squareroot(4sin^2t + 9cos^2t + 16k^2)
the book says the speed is 2 * squaroot(5)
i have no idea how to get that from where i left it off.