If a + b + c = 2 \(\frac{1}{a}\) + \(\frac{1}{b}\) + \(\frac{1}{c}\) = 0 ac = \(\frac{4}{b}\) , a3 + b3 + c3 = 28, then Find a2 + b2 + c2 |
7 8 9 10 |
8 |
Formula used → a3 + b3 + c3 - 3abc = (a + b + c) (a2 + b2 + c2 - ab - bc - ca)......(i) If ac = \(\frac{4}{b}\) ⇒ acb = 4 Now; \(\frac{1}{a}\) + \(\frac{1}{b}\) + \(\frac{1}{c}\) = 0 \(\frac{bc + ca + ab}{abc}\) = 0 So, bc + ca + ab = 0 From (i) 28 - 3 (4) = (2) (a2 + b2 + c2 - 0) 16 = 2(a2 + b2 + c2) a2 + b2 + c2 = 8 |