multi_RK2

function xNew = multi_RK2(nSteps, t, x, tau)

tau1 = tau/nSteps;

xVec = zeros(2*nSteps+1,1);
tVec = t + tau1/2*(0:2*nSteps);
xVec(1) = x;
xVec(2) = x + tau1/2*f_Extrap(t,x);


for i = 3:2*nSteps+1

    xVec(i) = psi_RK2( tVec(i-2), xVec(i-2), xVec(i-1), tau1 );
end

xNew = xVec(end);