In[]:=
With{g=9.807,L=1},sol=NDSolveθ''[t]+
g
L
*Sin[θ[t]]==0,θ[0]==
Pi
2
,θ'[0]==0,θ[t],{t,0,10}
Out[]=
θ[t]InterpolatingFunction
Domain: {{0.,10.}}
Output: scalar
[t]
In[]:=
Plot[Evaluate[θ[t]/.sol[[1]]],{t,0,10}]
Out[]=
2
4
6
8
10
-1.5
-1.0
-0.5
0.5
1.0
1.5