Question

Find a ⋅ b. a = <5, 2>, b = <4, 5>

Answer 1

Answer:

  30

Step-by-step explanation:

For a = <xa, ya> and b = <xb, yb>, the dot product is the sum of products ...

  a·b = (xa)(xb) + (ya)(yb)

Substituting the given information, you have ...

  a·b = 5·4 + 2·5 = 20 + 10

  a·b = 30

_____

Some graphing calculators can do such math. There are also dot product calculators available on the Internet. If you have quite a few of these to calculate, you can put the appropriate formula into a spreadsheet.