Evaluate the expression: v ⋅ w Given the vectors: r = ; v = ; w = ?

Question

Evaluate the expression: v ⋅ w Given the vectors: r = <5, -5, -2>; v = <2, -8, -8>; w = <-2, 6, -5> ?

welshfella · Answer

you multiply the corresponding components . This is called the scalar (or dot) propduct

kendellfawn · Answer

FLVS isn't clear on how to do this in the lesson. It's all over the place. Can you run me through it?

welshfella · Answer

v . w = <2, -8, -8> . <-2, 6, -5> = 2*2 can you continue?

welshfella · Answer

ooops   sorry 
the first part is 2 *-2 + -8*6 


what is the last  part?

kendellfawn · Answer

I'm looking back through the lesson and I can't seem to find it.. Give me a second?

welshfella · Answer

do you see the pattern?

kendellfawn · Answer

yes.

welshfella · Answer

its not that hard

kendellfawn · Answer

+-8*-5

welshfella · Answer

right 

so if you simpify  you'll get the scalar product  whwich is just a number , not a vector.  That is why its called the scalar product.

welshfella · Answer

i get it -4 - 48 + 40      agreed?

kendellfawn · Answer

Okay.. so 2 *-2 + -8*6 + -8*-5. Yes. -4-48+40. Thankyou so much for explaining it to me!

welshfella · Answer

yw