Following the examples shown in the textbook I was able to do the following: How
ID: 3031463 • Letter: F
Question
Following the examples shown in the textbook I was able to do the following:
However at this point I am at a loss as far as how to proceed, the only example in the textbook is as follows:
parrallelogram formed by (3a+b) and (a-b) if: ||a||= 1; ||b||= 3; and the angle formed by (a,b)= 30 degrees
they then show
=6 square units
I don't know how they jumped from one point to another, as this was the only example given in the textbook of how such a problem is to be tackled. without knowing the steps inbetween, I can't find a way to solve this question.
Explanation / Answer
Area = || (a-b) x (2a - 3b) ||
= || a x 2a - 3a x b - b x2a + b x3b ||
Now a x a = ; b xb =0 ; ax b = -b x a
So, = || a x 2a - 3a x b - b x2a + b x3b ||
= || -3a x b +a x b ||
= || -2a x b ||
= 2||a||*||b||*sin60
= 2*2*sqrt3*sqrt3/2
= 2*3 = 6 units