AboutAlon Mandes Expertise Kind of questions I can answer : Limits, Derivatives, Integration, Implicit functions, continuousity, differentiation ,Extremum problems, Lagrange multipliers, Gradients, Surface integrals, Multi variables functions ,Multi variables Integrals,Complex variables ,Complex functions, Curves, Trajectory integrals & Vector analyse,Divergence,Rotor & word problems.
Kind of question I can't answer : Economics,Combinatorics,infinite series & convergence ,Statistics & Probabilities .
Experience 1. I'm a team member of mathnerds (math site for answering questions)
2. I'm a team member in the Student's Union of the Technion, helping
students who have problems in mathematics.
3. 2 years of experience as a math teacher in college.
4. I give free homework help for high school students in
Mathematics & Physics.
5. I teach part time in collage the subjects : "Digital Signal Processing" , "Random Signals & Noise" ,
"Complex Functions".
Question Hi!! I'm trying to solve this system of equations using the Gaussian elimination method. can you help me?
2x-3y+2z=2
x+4y-z=9
-3x+y-5z=5
following instructions for Gaussian, I came up with
2 -3 2 2
1 4 -1 9
-3 1 -5 5
I then switched the first and second row:
1 4 -1 9
2 -3 2 2
-3 1 -5 5
then multiplied the first row by (-2) to get a zero in first position of the second row, and then multiplied the first row by 3 to get a zero in the first position third row
1 4 -1 9
0 -11 4 -16
0 13 -8 32
and now I'm stuck. does this look right to you, or did I do something wrong?
Thanks!!
Answer Ok, let's call the 1st row R1, the 2nd R2 & the 3rd R3.
Now we have the matrix :
1 4 -1 9
0 -11 4 -16
0 13 -8 32
We need to make another zero in R3. In order to do that we perform :
13R2+11R3-->R3. That mean we will switch the row R3 by 13R2+11R3.
Let's do it : 13R2 = 0 -143 52 -206 , 11R3 = 0 143 -88 352
13R2+11R3 = 0 0 -36 146. Hence, our Matrix is :
1 4 -1 9
0 -11 4 -16
0 0 -36 146
The solution will be :
z=146/(-36)=1.27
-11y+4*146/(-36)=-16 --> y=1.91
x+4*1.91-1.27=9 -- > x=-6.4
