An algebra problem by Albert Go

Algebra Level 1

log 4 ( ( log 4 ( 256 64 ) sin 3 2 cos 1 3 + cos 3 2 sin 1 3 ) 2 log 2 4 ) 1 \log_4\left(\left(\frac {\log_4 \left(\frac {256}{64}\right)}{\sin 32^\circ \cos 13^\circ + \cos 32^\circ \sin 13^\circ}\right)^{2\log_2 4}\right) - 1

Simplify the expression above.


The answer is 0.

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3 solutions

Vaibhav Prasad
Feb 23, 2015

log 4 { [ log 4 256 64 sin 32 cos 13 + cos 32 sin 13 ] 2 log 2 4 } 1 \log _{ 4 }{ \{ { [\frac { \log _{ 4 }{ \frac { 256 }{ 64 } } }{ \sin { 32 } \cos { 13 } +\cos { 32 } \sin { 13 } } ] }^{ 2\log _{ 2 }{ 4 } } } \} \quad -1\quad

= log 4 { [ log 4 256 64 sin 45 ] 2 log 2 4 } 1 =\log _{ 4 }{ \{ { [\frac { \log _{ 4 }{ \frac { 256 }{ 64 } } }{ \sin { 45 } } ] }^{ 2\log _{ 2 }{ 4 } } } \} \quad -1

= log 4 { [ log 4 256 64 1 / 2 ] 2 log 2 4 } 1 =\log _{ 4 }{ \{ { [\frac { \log _{ 4 }{ \frac { 256 }{64 } } }{ 1/\sqrt { 2 } } ] }^{ 2\log _{ 2 }{ 4 } } } \} \quad -1

= log 4 { [ 2 × log 4 256 64 ] 2 log 2 4 } 1 =\log _{ 4 }{ \{ { { [\sqrt { 2 } \times \log _{ 4 }{ \frac { 256 }{64 } } }{ }] }^{ 2\log _{ 2 }{ 4 } } } \} \quad -1

= log 4 { [ 2 × log 4 4 ] 2 log 2 4 } 1 =\log _{ 4 }{ \{ { { [\sqrt { 2 } \times \log _{ 4 }{ 4 } }] }^{ 2\log _{ 2 }{ 4 } } } \} \quad -1

= log 4 { [ 2 × 1 ] 2 log 2 4 } 1 =\log _{ 4 }{ \{ { { [\sqrt { 2 } \times 1 }] }^{ 2\log _{ 2 }{ 4 } } } \} \quad -1

= log 4 { [ 2 ] 2 log 2 4 } 1 =\log _{ 4 }{ \{ { { [\sqrt { 2 } }] }^{ 2\log _{ 2 }{ 4 } } } \} \quad -1

= log 4 { [ 2 ] 4 } 1 =\log _{ 4 }{ \{ { { [\sqrt { 2 } }] }^{ 4 } } \} \quad -1

= 4 log 4 { 2 } 1 =4\log _{ 4 }{ \{ \sqrt { 2 } } \} \quad -1

= 2 log 2 { 2 } 1 =2\log _{ 2 }{ \{ \sqrt { 2 } } \} \quad -1

= log 2 { 2 } 1 =\log _{ \sqrt { 2 } }{ \{ \sqrt { 2 } } \} \quad -1

= 1 1 =1\quad -1

= 0 = 0

Awesome solution!!!!!

Harsh Shrivastava - 6 years, 3 months ago

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Isme awesome kya tha yaar, ye simple question to tha !!!!!!!!!!

Vaibhav Prasad - 6 years, 3 months ago
Chew-Seong Cheong
Jun 12, 2018

x = log 4 ( ( log 4 ( 256 64 ) sin 3 2 cos 1 3 + cos 3 2 sin 1 3 ) 2 log 2 4 ) 1 Note that sin ( A + B ) = sin A cos B + cos A sin B = log 4 ( ( log 4 ( 4 ) sin 4 5 ) 2 × 2 ) 1 = log 4 ( ( 1 1 2 ) 4 ) 1 = log 4 ( ( 2 1 2 ) 4 ) 1 = log 4 ( 2 2 ) 1 = log 4 ( 4 ) 1 = 1 1 = 0 \begin{aligned} x & = \log_4\left(\left(\frac {\log_4 \left(\frac {256}{64}\right)}{\blue{\sin 32^\circ \cos 13^\circ + \cos 32^\circ \sin 13^\circ}}\right)^{2\log_2 4}\right) - 1 & \small \blue{\text{Note that }\sin (A+B) = \sin A \cos B + \cos A \sin B} \\ & = \log_4\left(\left(\frac {\log_4 \left(4\right)}{\blue{\sin 45^\circ}}\right)^{2\times 2}\right) - 1 \\ & = \log_4\left(\left(\frac 1{\frac 1{\sqrt 2}}\right)^4\right) - 1 \\ & = \log_4\left(\left(2^\frac 12 \right)^4\right) - 1 \\ & = \log_4\left(2^2\right) - 1 \\ & = \log_4\left(4\right) - 1 \\ & = 1 - 1 = \boxed{0} \end{aligned}

How did you compute sin32cos12 + cos32sin12 ???🤔🤔🤔🤨🤨🤨🤨🤨🤨

Vedant Saini - 3 years ago

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I have added a note.

Chew-Seong Cheong - 3 years ago

Sorry got it My mistake

Vedant Saini - 3 years ago

How is sin(32)cos(13)+cos(32)sin(13) = sin(45) ??

Nishant Ranjan - 1 year, 6 months ago

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See the note above.

Chew-Seong Cheong - 1 year, 6 months ago
Albert Go
Feb 12, 2015

First work inside the bracket. The numerator is equivalent to log4(256)-log4(64) = 4-3 = 1. The Denominator used the addition formula. It is equal to sin(32+13)=sin45=sqt2 over 2. Then get the reciprocal of sqt 2 over 2, which is simply sqt2! Next is the exponent. 2log2(4) = 2x2log2(2)=2x2 = 4. sqt2 raised to 4 is 4. log4(4)=1 and lastly 1-1=0. zero (0) is the final answer :)))

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