Need help pls: Two vectors are given by?

Question

a(with arrow pointing to left on top)=(4.0m)i - (3.0m)j + (1.0m)k
b(with arrow pointing to left on top)=(-1.0m)i+(1.0m)j+(4.0m)k.

In unit-vector notation, find (a) a + b, (b) a - b and, (c) a third vector c such that a - b + c = 0.

Please explain with the answer so that i understand the process rather than just get the answer. Thanks! xoxo

Answer 1

OK, First do the calculation (a+b) or (a-b) or whatever, component by component. In the a+b case, you wind up with 3i-2j+5k. To find the unit vector for (a+b), take 3^2+2^2+5^2= 38 and take the square root. The unit vector is then (a+b)/sqrt(38).

In part b, you will get 5i-4j-3k. The vector "c" is such that c+(answer to b)= 0.