Question

24. diketahui |a| = 3, |b| = 5 dan |a + b| = 6. maka |a - b| =...

Answer 1

(a-b)^2=a^2+b^2-2abcosx .... (1)

(a+b)^2=a^2+b^2+2abcosx .... (2)

(1)+(2)

(a-b)^2+(a+b)^2=2(a^2+b^2)

(a-b)^2+(6)^2=2(3^2+5^2)

(a-b)^2=32

|a-b|=4sqrt2