- #1
Vitani11
- 275
- 3
Homework Statement
An equation of motion for a pendulum:
(-g/L)sinΦ = Φ(double dot)
Homework Equations
L = length
g = gravity
ω = angular velocity
Φο = initial Φ
The Attempt at a Solution
The solution is Φ=Asinωt+Bcosωt
solving for A and B by setting Φ and Φ(dot) equal to zero respectively gives:
Φ= Φοcosωt
My question is how can you just go ahead and write down Φ=Asinωt+Bcosωt? My professor said it was because this was the only function that when differentiated twice give -sinωt but I can't just take that for what it is because I need to know how to arrive there.