# How do I find the dot product of vectors #v =5i-2j# and #w=3i+4j#?

##### 1 Answer

Dec 31, 2014

The dot product is a scalar obtained by multiplying the corresponding components of the two vectors and adding (algebraically) the results.

So you have:

You may check your result by plotting your vectors and using the alternative definition of dot product:

i.e.: the product of the modulus of the vectors times de cosine of the angle between them.

After some inverse trigonometry and Pitagora's Theorem I got:

and

so that: