Calculate the scalar projection and projection of (5,3) onto (7,-2)

Question

amistre64 · Answer

|dw:1366808943725:dw|

cant recall the def of a "scalar projection" to clearly tho

amistre64 · Answer

essentially you take the unit of v (the onto vector) and multiply it by the |u| cos(a), where a is the angle between them

anonymous · Answer

Ok, so how would you calculate it through the coordinates they gave me?

amistre64 · Answer

$$cos(\alpha)=\frac{u\cdot v}{|u|~|v|}$$
$$|u|~cos(\alpha)=\cancel{|u|}\frac{u\cdot v}{\cancel{|u|}~|v|}=|proj_uV|$$

amistre64 · Answer

u =  (5,3)  ; length of u
v =  (7,-2) ; length of v
   ---------
    dot them

we will need to find these properties in order to plug them into the formula

amistre64 · Answer

hmmm, from the google i get that |u| cos(a) is defined as the SCALAR projection, the magnitude of proj_u V

anonymous · Answer

|dw:1366809318162:dw|