Magnitude of a vector

Question

If A = 6i -8j and B = - 16i + 5j , what is the magnitude of the vector C = 2A - B ?

 

 

Answer 1

The magnitude of Vector C consists of 2A-B.

if A= 6i-8j then 2A= 12i-16j

Knowing that B= -16i+5j, then C=(12i-16j)-(-16i+5j)=28i-21j

So, the Magnitude of C is |C|=sqrt[(28)²+(-21)²]=sqrt (784+441)=35

I hope that helps

Answer 2

2A = <12,-16>

-B = <16,-5>

_________________

2A-B=<28,-21>  ALSO known as 28i - 21j

 

Now find the magnitude!

Note: I just fixed a little arithmetic error.