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Blazing goIITian

Joined:	19 Mar 2012
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22 Aug 2012 23:26:10 IST

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250

plz solve ........

Engineering Entrance , JEE Main , JEE Advanced , Mathematics , Algebra

4^x+1 + 4 ^ 1-x = 10 . find x.

Comments (5)

KAREENA

Blazing goIITian

Joined: 19 Mar 2012

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22 Aug 2012 23:38:27 IST

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guyz plz solve this........

KAREENA

Blazing goIITian

Joined: 19 Mar 2012

Posts: 421

22 Aug 2012 23:52:34 IST

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???????????????????????????????

abhishek

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23 Aug 2012 12:19:57 IST

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4^x+1+4^1-x = 10

4^x + 4^1-x = 9

4^x + 4.4^-x = 9

4^x + 4/4^x = 9

4^2x + 4 = 9.4^x

let 4^x = a

a^2 + 4 = 9a

a^2 -9a + 4 = 0

solve this quadratic eq. and find value of a

then put 4^x in place of a and solve for x.............

Srujana

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23 Aug 2012 17:39:01 IST

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$\\4^{x+1} + 4 ^ {1-x} = 10\\\Rightarrow 4^x+4^{-x}=\frac{5}{2}\\Let\ 4^x=t\\ \\ \Rightarrow t+\frac{1}{t}=\frac{5}{2}\\ \\ \Rightarrow t=\frac{1}{2}, t=2\\ \\ \Rightarrow 2^{2x}=2^{-1}, 2^{2x}=2^1\\ \\ \Rightarrow x=\frac{-1}{2}, x=\frac{1}{2}$

KAREENA

Blazing goIITian

Joined: 19 Mar 2012

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24 Aug 2012 19:27:15 IST

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thankss

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