Calculating the determinant of a couple of matrices

Hi everyone.

Here I have two matrices that I would like help with, in calculating its' determinant!

The first one gotta have a nice trick to it, I am sure that going the longer way is not the only way!

First one:

http://i46.tinypic.com/1z1ydl0.png

Second one:

http://i49.tinypic.com/2jslzn.png

Thanks in advance!

Morad

Re: Calculating the determinant of a couple of matrices

Well the second one is easy because there are rows and columns that are almost entirely composed of zeroes.

Re: Calculating the determinant of a couple of matrices

For the first one you can do R1 goes to R1+R2+R3+R4 or C1 goes to C1+C2+C3+C4 and you will find that all the elements of R1 OR C1 will become (a+b+c+d). take it common and proceed now you will have all 1s in one Row / column