Saved Bookmarks
| 1. |
If a + b + c = 9 and AB + BC + CA = 40 then the value of a square + b square + c square |
|
Answer» a + b + c = 9 AB + bc + ca = 40 To find : a² + b² + c² The following expression matches to the ALGEBRAIC identity (a + b + c)² = a² + b² + c² + 2ab + 2bc + 2ac or (a + b + c)² = a² + b² + c² + 2( ab + bc + ac) Thus, (a + b + c)² = a² + b² + c² + 2(ab + bc + ac) substituting the values, we have, 9² = a² + b² + c² + 2( 40) 81 = a² + b² + c² + 80 Transposing 80 to LHS, we have, 81 - 80 = a² + b² + c² Thus, a² + b² + c² = 1 |
|