# DifferentialEquations.jl Tutorial on BV Porblem

Tthe tutorial section of DifferentialEquations.jl on Boundary Value Problems states that: " The third argument of `BVProblem` is the initial guess of the solution, which is constant in this example."

In this example the constant guess is u(t)=pi/2 and u’(t)=pi/2 for all t from the time interval. How can I make a nonconstant guess such as u(t)=sin(t) & u’(t)=cos(t)?

You just use an array of arrays, for example, `u = [[1.0].[2.0],[3.0]]`, matching the size of the solution.

Thanks for your response! But when I do that and I have an initial guess of the form u0 = [[0],[1],[2],…[lengthOfTheSolution]] then the solver throws the error: DimensionMismatch(“tried to assign 62 elements to 1 destinations”) where 62 is the designated length of the solution.

I thought maybe you meant for the pendulum for example where the solution is two dimensional, that u0 would need to be u0= [ [0,0],[1,1],[2,3],…[lengthOfSolution, lengthOfSolution] ] but this throws the exact same error.

Ahh open an issue because that should be it. Include the code you ran.