Question

Find the sum of
d₁=15i + 30j + 12k
d₂=23i - 14j - 5k
d₃= -13i + 15j

Answer 1

Given:

${\bf d}_1=15{\bf i}+30{\bf j}+12{\bf k};$

${\bf d}_2=23{\bf i}-14{\bf j}-5{\bf k};$

${\bf d}_3=-13{\bf i}+15{\bf j}.$

The sum of vectors

$${\bf d}_1+{\bf d}_2+{\bf d}_3=15{\bf i}+30{\bf j}+12{\bf k}+$$ $$+23{\bf i}-14{\bf j}-5{\bf k}-13{\bf i}+15{\bf j}=25{\bf i}-31{\bf j}+7{\bf k}.$$