Polynomial Manipulation

Algebra Level 4

If x , y x, y and z z satisfy 1 x + 1 y + 1 z = 0 \frac { 1 }{ x } + \frac {1 }{y } + \frac {1 }{z } = 0 x 2 + y 2 + z 2 = 2 , x^{2}+y^{2}+z^{2}=2, what is ( x + y + z ) 12 ? \left( x+y+z \right) ^{12}?


The answer is 64.

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

Vedant Mittal
Apr 16, 2014

\frac { 1 }{ x } +\frac { 1 }{ y } +\frac { 1 }{ z } =\frac { xy+yz+zx }{ xyz } =0\quad \therefore \quad xy+yz+zx=0\\ \\ \Rightarrow \quad ({ x+y+z }^{ 2 })={ x }^{ 2 }{ +y }^{ 2 }+{ z }^{ 2 }+2(xy+yz+zx)\\ \Rightarrow \quad x+y+z=\pm \sqrt { 2+0 } \\ \Rightarrow x+y+z=\pm \sqrt [ 2 ]{ 2 } \\ \Rightarrow ({ x+y+z) }^{ 12 }={ \sqrt [ 2 ]{ \pm 2 } }^{ 12 } =64

nice solution

georg kerolos - 7 years, 1 month ago

Typo in the second line ( x + y + z 2 ) (x+y+z^2) should be ( x + y + z ) 2 (x+y+z)^2

Shriram Lokhande - 6 years, 11 months ago

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...