Question

What is the projection of `<5,6,1 >` onto `<8,-5,1 >`?

Answer 1

`vec C= <88/90 ,-55/90,11/90>`

Explanation:

`vec A= < a,b,c >`
`vec B= < d,e,f >`
`"Projection of A onto B is given as :"`
`vec C= (vec A .vec B)/(||vec B||^2)vec B`
`vec A* vec B=a.d+b.e+c.f=40-30+1=11`
`"magnitude of "vec B=sqrt (64+25+1)=sqrt 90`
`vec C=11/90<8,-5,1>`
`vec C= <88/90 ,-55/90,11/90>`