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(x^2-4x)^2-(x-4)^2-16=0

2007-04-30 19:43:00 · 6 answers · asked by sneha r 2 in Science & Mathematics Mathematics

6 answers

Are you sure this is copied correctly? It is close in some ways to what would be a quite elegant problem, but in its present form, it has to be multiplied out to get an unfactorable quartic equation and can only be solved numerically.

The TI-83 gives roots of

x1 = -2.565994563312
and
x2 = 4.8439519121702

Those are the ugly irrational roots to the problem you posed. Once again, are you sure this was copied correctly?

2007-04-30 19:55:03 · answer #1 · answered by athenianmike 2 · 0 1

(x^2 - 4x)^2 - (x - 4)^2 - 16 = 0
x^4 - 8x^3 + 15x^2 + 8x - 32 = 0
(x - 4.843951913)(x + 1.256599458)
x^2 - 3.587352455x - 6.086907348)(x^2 + ax + 5.257185327) = x^4 - 8x^3 + 15x^2 + 8x - 32
- 3.587352455 + a = - 8
a = - 4.412647545
x^2 + - 4.412647545x = - 5.257185327
x^2 + - 4.412647545x + 4.867864589 = - 5.257185327 + 4.867864589

(x - 2.2063237725)^2 = - 0.3893207379

x - 2.2063237725 = ± j0.6239557179

x = 2.2063237725 - j0.6239557179
x = 2.2063237725 - j0.6239557179
x = 4.843951913
x = - 1.256599458

2007-04-30 21:02:57 · answer #2 · answered by Helmut 7 · 0 1

Simplify the given equation:
(taking x common from the first bracket)
x^2(x-4)^2-(x-4)-16=0
now put x-4 = t
thus x= t+4. substituting,
(t+4)^2 t^2 - t -16 = 0
opening the brackets ,
t^4 + 8t^3 + 16t^2 - t - 16 =0
this equation can be solved by polynomial solving of equations.(which i cant explain properly)

2007-04-30 19:55:52 · answer #3 · answered by sweety 2 · 0 2

(x^2-4x)^2=x^4 - 2*x^2*4x + 16x^2= x^4 - 8x^3 + 16x^2
(x-4)^2 = x^2 - 2*x*4 - 4^2 = x^2 - 8x - 16
(x^2-4x)^2 - (x-4)^2 -16 = x^4 - 8x^3 + 16x^2 - ( x^2-8x-16) -16
= x^4 - 8x^3 + 16x^2 - x^2 + 8x + 16-16
=x^4 -8x^3 -15X^2 +8x

2007-04-30 19:56:26 · answer #4 · answered by rajesh 2 · 0 2

on expansion you will get ;
17x^2 - 16x^3 + 8x - 16 =0

2007-04-30 20:08:35 · answer #5 · answered by Akshay I 1 · 0 2

What the **** know one well figure out that unless there smart enoth and I can't you shold've made an eiser one!

2007-04-30 19:52:50 · answer #6 · answered by Kamek 2 · 0 3

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