How to get equation for velocity of Pendulum

[ortegavs]

Homework Statement

Homework Equations

T=2pi(sq.root L/g)

The Attempt at a Solution

combined a=1/2 V^2/r with a=g(sinO) then solved for v.
got v=Sq.root 2gL(sinO). Don't know if this is right.

 

[Delphi51]

I doubt if that approach works - the one acceleration is vertical while the other is radial.

I suggest beginning with the equation of motion
θ = θo*cos(2πt/T)