Finding a vector using scalar and vector projections

user8899
Messages
12
Reaction score
0

Homework Statement



Determine the vector(s) whose vector projection on u =< 1,2,2 > is v =< 3,6,6 > and its
scalar projection on w =< 1,1,1 > is √3.

Homework Equations


Vector Projection of b onto a: (|b.a| \ |a|) * (1/ |a|) * a
Scalar Projection: (|b.a| \ |a|)


The Attempt at a Solution


First started by finding the vector <a,b,3-b-c> (using the scalar projection equation), but don't know what else to do from there. Help please?
 
Physics news on Phys.org
welcome to pf!

hi user8899! welcome to pf! :smile:
user8899 said:
First started by finding the vector <a,b,3-b-c> (using the scalar projection equation) …

isn't the scalar projection just the magnitude of the vector projection? :wink:
 
Hi, Thank you!

well I substituted <a,b,3-b-c> into the vector projection equation, but I think my problem is the algebra... I'm not sure
 
what is your vector projection equation? :smile:
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...

Similar threads

Back
Top