# Trying to resolve a BVProblem

Hello dear all,

I am currently trying to resolve a BVProblem. Thus I came back to an example given in the Boundary Value Problems section.
If I use the code as follows:

``````using BoundaryValueDiffEq
using OrdinaryDiffEq, Plots

const g = 9.81
L = 1.0
tspan = (0.0,pi/2)

function simplependulum(t,u,du)
θ  = u
dθ = u
du = dθ
du = -(g/L)*sin(θ)
end

function bc(residual, ua, ub)              # ua = beginning of time span, ub = end
residual = ua + pi/2             # solution at the beginning of time span (-pi/2)
residual = ub - pi/2             # solution at the end of time span should (pi/2)
end

bvp = TwoPointBVProblem(simplependulum, bc, [pi/2,pi/2], tspan)
sol = solve(bvp, MIRK4(), dt=0.05)
plot(sol)
``````

I obtain an error related to:

``````sol = solve(bvp, MIRK4(), dt=0.05)
``````
``````LoadError: MethodError: no method matching simplependulum(::Array{Float64,1}, ::Array{Float64,1}, ::DiffEqBase.NullParameters, ::Float64)
``````

May I ask you some help?
It is perfectly right. 