Hard to simplify?

Algebra Level 3

If α , β \alpha,\beta are the roots of the quadratic equation

x 2 ( 3 + 2 log 2 3 3 log 3 2 ) x 2 ( 3 log 3 2 2 log 2 3 ) = 0 x^2-\left( 3+2^{\sqrt{\log_23}}-3^{\sqrt{\log_32}} \right)x-2\left( 3^{\log_32}-2^{\log_23} \right) =0 ,

then find the value of ( α 2 + α β + β 2 ) \left( \alpha^2+\alpha\beta+\beta^2 \right) .


The answer is 7.000.

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2 solutions

Ayush Verma
Dec 11, 2014

Lets try to get the equation in the simpler form. Firstly we will try solving out the " log \log " terms in the equation.

2 log 2 3 = 2 log 2 3 log 2 3 = 2 ( log 2 3 ) ( log 3 2 ) = ( 2 ( log 2 3 ) ) log 3 2 = 3 log 3 2 \quad \quad \quad \quad \begin{array}{ll} { 2 }^{ \sqrt { \log _{ 2 }{ 3 } } } & ={ 2 }^{ \cfrac { \log _{ 2 }{ 3 } }{ \sqrt { \log _{ 2 }{ 3 } } } }\\ & ={ 2 }^{ \left( \log _{ 2 }{ 3 } \right) \left( \sqrt { \log _{ 3 }{ 2 } } \right) }\\ & ={ \left( { 2 }^{ \left( \log _{ 2 }{ 3 } \right) } \right) }^{ \sqrt { \log _{ 3 }{ 2 } } }\\ & ={ 3 }^{ \sqrt { \log _{ 3 }{ 2 } } } \end{array}

2 log 2 3 3 log 3 2 = 0. \quad \quad \quad \quad \Rightarrow { 2 }^{ \sqrt { \log _{ 2 }{ 3 } } }-{ 3 }^{ \sqrt { \log _{ 3 }{ 2 } } }=0 .

And we know the property of logarithms that a log a b = b a^{\log_a b}=b , we can figure out 3 log 3 2 2 log 2 3 = 2 3 = 1 { 3 }^{ \log _{ 3 }{ 2 } }-{ 2 }^{ \log _{ 2 }{ 3 } }=2-3=-1 . So now our equation becomes x 2 3 x + 2 = 0 { x }^{ 2 }-3x+2=0 . Hence using Vieta's Formula we can conclude that α + β = 3 \alpha+\beta=3 and α β = 2 \alpha \beta=2 . So we will solve it further as we move on:

α 2 + α β + β 2 = ( α + β ) 2 α β = 3 2 2 = 7. \quad \quad \quad \begin{array}{ll} { \alpha }^{ 2 }+\alpha \beta +{ \beta }^{ 2 }& ={ \left( \alpha +\beta \right) }^{ 2 }-\alpha \beta \\ & ={ 3 }^{ 2 }-2 \\ & =7 .\square \end{array}

Heart touching question with heart touching solution

U Z - 6 years, 6 months ago

lol, what i actual get is 3...

Soh Tiong - 6 years, 5 months ago

Sorry, but i don't understand about the first equation. Can you explain it??

Fidel Simanjuntak - 4 years, 11 months ago

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sqrt(x) = x/sqrt(x)

Mauricio de Oliveira - 3 years ago

Awesome solution! I used calculator but now I understood! Thanks !😀

Anurag Pandey - 4 years, 10 months ago

How did u directly do the first step

Pranav Jayaprakasan UT - 4 years, 7 months ago

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i was trying to make base same

Ayush Verma - 4 years, 4 months ago

Now i understood

Pranav Jayaprakasan UT - 4 years, 7 months ago

Nice solution boy

Pranav Jayaprakasan UT - 4 years, 7 months ago

Thank you sir It was amazing

Shailesh Singh - 8 months, 3 weeks ago
Isaías Batista
Dec 31, 2014

( α + β ) 2 = α 2 + 2 α β + β 2 (\alpha+\beta )^{2}=\alpha^{2}+2\alpha\beta+\beta^{2}

α 2 + α β + β 2 ) = ( α + β ) 2 α β \alpha^{2}+\alpha\beta+\beta^{2} )=(\alpha+\beta)^{2}-\alpha\beta

α + β = B A , α β = C A \alpha+\beta=-\frac{B}{A}, \alpha\beta=\frac{C}{A}

A = 1 , B = ( 3 + 2 l o g 2 3 3 l o g 3 2 ) , C = 2 ( 3 l o g 3 2 2 l o g 2 3 ) A=1 , B=-( 3+2^{\sqrt{log_{2} 3}}-3^{ \sqrt{log_{3} ⁡2}}), C=-2(3^{log_{3} ⁡2}-2^{log_{2} ⁡3})

( α 2 + α β + β 2 ) = ( B A ) 2 C A = B 2 C (\alpha^{2}+\alpha\beta+\beta^{2} )=(-\frac{B}{A})^{2}-\frac{C}{A}=B^{2}-C

= ( 3 + 2 l o g 2 3 3 l o g 3 2 ) 2 + 2 ( 3 l o g 3 2 2 l o g 2 3 ) = 3 2 + 2 ( 1 ) = 9 2 = 7 =( 3+2^{\sqrt{log_{2} 3}}-3^{ \sqrt{log_{3} ⁡2}})^{2}+2(3^{log_{3} ⁡2}-2^{log_{2} ⁡3})=3^{2}+2(-1)=9-2=7

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