Hi!

I am trying to create a function that I could use to solve a simple linear dynamic problem by using DifferentialEquations.jl.

```
using DifferentialEquations
using Plots
function s(f,KK,MM,al,be,n,u0,t)
C=al*MM+be*KK
A=[C*Mi K*Mi;eye(n) zeros(n,n)]
b=[f(t);zeros(n)]
g(u,p,t)=A*u+b
prob=ODEProblem(g,u0,tspan)
sol=solve(prob)
h=plot(sol)
display(h)
end
```

When I test the function with values something goes wrong e.g.

```
M=400; m=35
K=50000; k=200000
A=300
function f(t)
[A*sin(t);0]
end
MM=M*0.5*eye(2)+0.5*m*eye(2)
KK=[K+k -K;-K K]
Mi=inv(MM)
tspan=(0.0,2.0)
u0=zeros(4,1)
f(t)=[A*sin(t);0]
al=0.5; be=0.02; n=2
s(f,KK,MM,al,be,n,u0,tspan)
```

I keep getting this error message:

```
LoadError: e[91mMethodError: no method matching sin(::Tuple{Float64,Float64})e[0m
Closest candidates are:
sin(e[91m::Float64e[39m) at math.jl:419
sin(e[91m::Float32e[39m) at math.jl:420
sin(e[91m::Float16e[39m) at math.jl:950
...e[39m
```

Does anyone have any suggestions how I could try to fix this?