If a2 + b2 + c2 = 6.25 and (ab + bc + ca) = 0.52, What is the value of (a + b + c) ?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. ± 2.7
Concept used : (a + b + c)2 = a2 + b2 + c2 + 2(ab + bc + ca).
Given :
1. a2 + b2 + c2 = 6.25
2. (ab + bc + ca) = 0.52
Now (a + b + c)2 = 6.25 + 2(0.52)
(a + b + c)2 = 6.25 + 1.04
(a + b + c) = (7.29)1/2
(a + b + c) = ± 2.7