VECTORS 1

If u = 6i + 2j and v = 3i + 10j find 5u - 3v

solution

= 5u + 3v

= 5(6i + 2j) - 3(3i + 10j)

= 30i + 10j - 9i - 30j

= (30i - 9i) + (10j - 30j)

= 21i - 20j

Hence 5u - 3v = 21i + 20j .

TRY THIS..................

NECTA 2001 QN. 12a (i)

If u = 4i + 3j and v = 2i + 4j;  find 2u + 3v.