Well my question pertains to X4 which is the 4th column. I wrote down what the Matrix A is in A=[]
I have to find C which will be X2 and X4 combined into a matrix.
N(A) is the nullspace of A
R(C) is the rowspace of C
Sorry I should have mentioned that from the start I hope this is enough...
well i found out the velocity at the time of collision 1st with v^2 =vi^2 +2a(x-xi) to be 49.05 and then using the 1st equation i got the time to be 5.6 or 5.599
edit: if your homework was anything like mine then it was probably asking for that too and i found it easier to get that answer 1st