Machine-translated by Google. Questions are authored in English.
Top

Discussion

If a, b, c are real numbers such that \((a - 2)^{2} + (b - 2)^{2} + (c - 2)^{2} = 0\)

  • A.\(a, b, c\) are in G.P. and \(a + b + c = 6\)
  • B.\(a, b, c\) are in G.P. and \(a + b + c = 4\)
  • C.\(a, b, c\) are not in G.P.
  • D.\(a, b, c\) are in G.P. and \(a + b + c = 8\)
  • E.\(a, b, c\) are not in G.P. and \(a + b + c = 16\)

Answer: A

a, b, c are in G.P. and \(a + b + c = 6\).

A sum of squares of real numbers is zero only if each square is zero, so \(a = b = c = 2\). Three equal non-zero numbers form a G.P. with common ratio 1 (and also an A.P.), and their sum is 6.

The options with sums 4, 8 or 16 have the wrong total, and 'not in G.P.' is false because a constant non-zero sequence is geometric.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.