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Tamil Nadu Board of Secondary EducationHSC Science Class 11

Prove that log2+16log 1615+12log 2524+7log 8180 = 1 - Mathematics

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Question

Prove that `log 2 + 16log  16/15 + 12log  25/24 + 7log  81/80` = 1

Sum
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Solution

`log 2 + 16log  16/15 + 12log  25/24 + 7log  81/80`

= `log 2 + log   (16/15)^16 + log  (25/24)^12 + log  (81/80)^7`

=`log 2 + log  (2^4/(3 xx 5))^16 + log  (5^2/(2^3 xx 3))^12 + log  (3^4/(2^4 xx 5))^7`

= `log [2 xx (2^4/(3 xx 5))^16 xx  (5^2/(2^3 xx 3))^12 xx (3^4/(2^4 xx 5))^7]`

= `log  [2 xx 2^64/(3^16 xx 5^16) xx 5^24/(2^36 xx 3^12) xx 3^28/(2^28 xx 5^7)]`

= `log [(2^65 xx 5^24 xx 3^28)/(3^28 xx 5^23 xx 2^64)]`

= log 2 × 5

= log1010

= 1

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Chapter 2: Basic Algebra - Exercise 2.12 [Page 80]

APPEARS IN

Samacheer Kalvi Mathematics - Volume 1 and 2 [English] Class 11 TN Board
Chapter 2 Basic Algebra
Exercise 2.12 | Q 7 | Page 80
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