1. The problem statement, all variables and given/known data x(t) = Asin (Wt + z) Define values for A(amplitude) and z(angle) so that: x(0) = x0 and x´(0) = v0 2. Relevant equations Chain rule. 3. The attempt at a solution Im pretty sure I got the z part right: x(0) = Asin(z) = x0 x´(0) = AWcos(z) = v0 Solve simultaneous equations for z: sin(z)/cos(z) = (x0/a)(AW/v0) tan(z) = (x0W/v0) z = tan^-1(x0W/v0) As for the A part I have no idea how to go about solving it: Rearranging the x(0) equations for A Asin(z) = x0 AWcos(z) = v0 A=x0/sin(z) A=v0/Wcos(z) Now what?