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Expert: - 1/25/2012


Question
Hello sir, can you PLEASE show me the correct way to get the solutions for (using either e, ln, or logs):

B)X^2.3=112
C)3x^-2x=15

Thanks a million.

Answer
B) x^2.3=112

  x = (112)^ (1/2.3)=7.7797 (shown)

  You don't need to use logarithms for this.

C) 3x^-2x=15  
  3* (x^x)^-2 =15
  (x^x)^2 = 1/5
   x^x = +1/sqrt(5)  or -1/sqrt (5)

  Note that there will be no solutions to this since the curve for y=x^x will never intersect that of y=+1/sqrt(5) or y=-1/sqrt(5)   

Hope this helps. Peace.  
     
PS: Your questions are not trigonometry related.

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Frederick Koh

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I can answer questions concerning calculus, complex numbers, vectors, statistics , algebra and trigonometry for the O level, A level and 1st/2nd year college math/engineering student.

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3 years helping out in a singaporean youth forum: http://forums.sgclub.com/math_help/ (under the moniker whitecorp) You can also visit my main maths website http://www.whitegroupmaths.com where I have designed "question locker" vaults to store tons of fully worked math problems. Peace.

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