### Raw Transcript

This video is on cross product. Many people have asked for it and I’m going to do it in my fabulous programs. Press 2nd alpha, to get the letters, enter index, 2nd alpha again and 8 (). So you should have, index 8 () to get to my menu. Go to cross product, press enter. It has for vector A and you press alpha to put anything in the empty lines in all my programs. This is the way the calculator operates. Then we’re gonna press alpha 8, press enter twice, input alpha -6 enter twice, alpha 4 and enter twice. These are for the vector A. For vector B, enter alpha 4, press enter twice, alpha -8 remember the negative sign is different from the minus sign for equations. Enter the y component of the B vector alpha -9 enter twice, z is alpha 4 enter twice. This is what we’ve entered: A = <8., -6., 4.> B = <-8., -9., 4.> Select ok (or change if you want) Now up comes the menu for all vectors and those things we’ll be able to do it. Here we have cross products, A x B cross product which is different from B x A cross product. I do both of them for me and you. Gonna do A x B first. Here are the vectors: A x B (cross product) =

= < 8., -6., 4.,>

X <-8., -9., 4>

Matrix multiplication

= <8., -6., 4.>

<-8., -9., 4.>

Press enter and see the calculations for i,k,j vectors or coordinates

=[(-6.) (4.) – (4.) (-9.)] i –

[(8.) (4.) – (4.) (-8.)] j +

[(8.) (-9.) – (6.) (-8.)] k

Enter and it keeps doing the multiplications

= [(-24.) – (-36.)] i –

[(32.) – (-32.)] j +

[(-72.) – (48.)] k

= 12i – 64j 120k (i,j,k system)

= (vector notation)

Now B x A cross product and here are the calculations

=[(-9.) (4.) –

(4.) (-6.)] i –

[(-8.) (4.) –

(4.) (8.)] j +

[(-8.) (-6.) –

(-9.) (8.)] k

Down on the page, do them all perfect

=[9-36.) – (-24.)] i –

[(-32.) – (32.)] j +

[(48.) – (-72.)] k

= -12.i + 64. J + 120. K

= <-12., 64., 120.>

Pretty neat, everystepcalculus.com, buy my programs you’ll be thrilled.

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