Question

Dados os vetores: A = 3i – 4j B= 5i + 8j C= -3i +2j Determine os valores: a)A-B; b) A+3C-5B; c) A+B; d) |A|; e) |A+C|

Answer 1

A = 3i – 4j B= 5i + 8j C= -3i +2j

a)A-B = 3i – 4j -( 5i + 8j ) ==>  3i – 4j - 5i - 8j ==> - 2i - 13j 

b) A+3C-5B = 3i – 4j + 3(5i + 8j) - 5(-3i +2j )==> 3i – 4j + 15i + 24j + 15i - 10j

==>  33i + 10j

c) A+B =3i – 4j + 5i + 8j ==>   8i + 4j 
                _____       ____      __
d) |A| =  √3²+4²   = √9+16 = √25 ==> 5 
                                                                          ______   
e) |A+C| = | 3i – 4j - 3i +2j | ==> | 0i - 2j | ==> √0²+(-2)² ==> √4 ==> 2