It's causing me headache....
0.471214x^3 - 5.763154x^2 = 285.7213
What is x?
2007-05-16 21:05:45 · 8 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
This is the same as solving
0.471214x^3 - 5.763154x^2 - 285.7213 = 0
There is a little-known formula for solving cubics:
http://www.math.vanderbilt.edu/~schectex/courses/cubic/
...although you will see that it is rather more complicated than the quadratic formula.
If I were doing this, I would plot the graph of
y = 0.471214x^3 - 5.763154x^2 - 285.7213
and look for how many times it crossed the x-axis for how many solutions there are.
(I just did this and it crosses once, near x = 15, concurring with previous answers. I did it on a computer and had to zoom in to confirm that it only crosses once.)
I would then use a numerical method such as Newton-Raphson
http://en.wikipedia.org/wiki/Newton's_method#Description_of_the_method
2007-05-16 21:25:44 · answer #1 · answered by joncummins1968 4 · 1⤊ 0⤋
Kinda tricky problem ain't it
Well after extensive solving I got the answer to be 14.945
If you use a scientific calculator it becomes a little easier and you still get the same answer(it continues to more places of decimals)
2007-05-17 04:50:47 · answer #2 · answered by oolala 2 · 0⤊ 1⤋
It's a cubic equation.
Anyways x=14.9452
2007-05-17 04:09:30 · answer #3 · answered by Anonymous · 0⤊ 0⤋
it is a little complicated problem.
using a scientific calci i got x = 14.945
2007-05-17 04:28:22 · answer #4 · answered by Charu Chandra Goel 5 · 0⤊ 0⤋
x = 14.94515112
Solved numerically
2007-05-17 04:27:09 · answer #5 · answered by Helmut 7 · 0⤊ 0⤋
8 i jus worked it out sorry i cant put the work it too much
2007-05-17 04:09:18 · answer #6 · answered by winegeartr 2 · 0⤊ 3⤋
It might not have analytic solution.
2007-05-17 04:09:54 · answer #7 · answered by moosadarya 3 · 0⤊ 2⤋
x = 14.94515
2007-05-17 04:23:24 · answer #8 · answered by Zax 3 · 0⤊ 0⤋