The sum of two numbers is 6 times their geometric mean, show that numbers are in the ratio.

\( (3+2\sqrt{2}): (3-2\sqrt{2})\)

Asked by Abhisek | 1 year ago |  76

1 Answer

Solution :-

Consider the two numbers be a and b.

Then, G.M. = \( \sqrt{ab}\).

According to the conditions given in the question,

\( a+b=6\sqrt{ab}\) .........(1)

\( (a+b)^2=36\)

\( (a-b)^2= (a+b)^2-4ab\)

\( =36ab-4ab=32ab\)

\( a-b=\sqrt{32}\sqrt{ab}\)

\( =4\sqrt{2}\sqrt{ab}\) ..........(2)

Add (1) and (2).

\(2a= (6+4\sqrt{2})\sqrt{ab}\)

\( a= (3+2\sqrt{2})\sqrt{ab}\)

Substitute \( a= (3+2\sqrt{2})\sqrt{ab}\) in equation (1) .

\(b= 6\sqrt{ab}-(3+2\sqrt{2})\sqrt{ab}\)

b=\( (3-2\sqrt{2})\sqrt{ab}\)

Divide a by b .

\( \dfrac{a}{b}=\dfrac{(3+2\sqrt{2})\sqrt{ab}}{(3-2\sqrt{2})\sqrt{ab}}\)

\( \dfrac{(3+2\sqrt{2})}{(3-2\sqrt{2})}\)

Therefore, it is proved that the numbers are in the ratio.

Answered by Abhisek | 1 year ago

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