Practicing Success
If a = 345, b = 344, c = 343, then find a2 + b2 + c2 - ab - bc - ca. |
6 3 2 1 |
3 |
a2 + b2 + c2 - ab - bc - ca = \(\frac{1}{2}\) [(a - b)2 + (b - c)2 + (c - a)2] = \(\frac{1}{2}\) [(345 - 344)2 + (344 - 343)2 + (343 - 345)2] = \(\frac{1}{2}\) [1 + 1 + 4] = 3 |