NCERT Class XI Mathematics - Sequences and Series - Solutions
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Question : 62
Total: 106
The sum of two numbers is 6 times their geometric mean, show that numbers are in the ratio ( 3 + 2 √ 2 ) : ( 3 − 2 √ 2 ) .
Solution:
Let a and b be the two numbers such that a + b = 6 √ a b
⇒ a + b = 3( 2 √ a b ) ⇒
=
Applying componendo and dividendo, we have,
=
⇒
=
⇒
=
Again applying componendo & dividendo, we have
=
⇒
=
⇒
=
Squaring both sides, we get
=
=
⇒
=
Hence, proved.
⇒ a + b = 3
Applying componendo and dividendo, we have,
⇒
Again applying componendo & dividendo, we have
Squaring both sides, we get
Hence, proved.
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