In a given electrical network; the equations for the...

In a given electrical network; the equations for the currents $i_1$, $i_2$, $i_3$ are $3i_1 + i_2 + i_3 = -8$ $2i_1 - 3i_2 - 2i_3 = -5$ $7i_1 + 2i_2 - 5i_3 = 0$ Calculate $i_1$ and $i_3$ by using Gauss Elimination method.

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Transcript

00:01 Alright, so we want to calculate by the gaussian elimination method.

00:05 I turned them into x, y, and z just because it was easier to deal with that way.

00:11 We want to get 1.

00:15 So what did i do? i divided the second equation by 2.

00:21 And in doing so i got x minus 1 .5 y minus z is equal to negative 2 .5.

00:32 So i took that second equals, there we go, then i took, i just wrote those down.

00:41 Alright, 3x plus y plus z equals negative 8.

00:49 And 7x plus 2y minus 5z equals 0.

00:57 Okay, then i take, multiply that first one by 3 and then subtract.

01:05 Not sure which order i subtracted in yet.

01:08 Obviously, let me write those back down so i have the first one.

01:18 And 3 times x minus 3 is 0.

01:23 Here it is, negative point.

01:29 So it looks like i did 1 .5 times, negative 1 .5 times 3 minus 1 is a negative 5 .5y.

01:43 Negative 1 times 3 minus 1 is a negative 4z.

01:49 And negative 2 .5 times 3 minus 8 is 0 .5.

01:58 And i do the same thing for that third equation.

02:01 I'm going to multiply by 7 and subtract the third equation.

02:07 So 7x minus 7x is 0.

02:10 Negative 1 .5 times 7 minus 2 is negative 12 .5.

02:18 Negative 1 times 7 minus 5 is a negative 2z.

02:25 And a negative 2 .5 times 7 minus 0 was a negative 17 and a half...

Question

In a given electrical network; the equations for the currents $i_1$, $i_2$, $i_3$ are $3i_1 + i_2 + i_3 = -8$ $2i_1 - 3i_2 - 2i_3 = -5$ $7i_1 + 2i_2 - 5i_3 = 0$ Calculate $i_1$ and $i_3$ by using Gauss Elimination method.

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