Posted by Sam on Thursday, July 3, 2014 at 3:36pm.
How do I find x for this equation? I think I should get e^(something).
Thanks in advance!
Algebra - Steve, Thursday, July 3, 2014 at 5:45pm
There's no algebraic way to do it. A numeric method or a graphical analysis will be required. See
Algebra - Reiny, Thursday, July 3, 2014 at 5:46pm
For a complicated equation such as yours, the most powerful method is probably Newton's Method.
let y = 3x^2+4lnx+4
dy/dx = 6x + 4/x
newx = x - y/(dy/dx)
= x - (3x^2+4lnx+4)/(6x + 4/x)
which simplifies to
newx = (3x^2 - 4lnx)/(6x + 4/x)
now use an iteration process, I started with x = 1
x | newx
1 -- .3
.3 -- .336072..
.336072 -- .337716
.337716 -- .337719143
.337719143 -- .337719143
since the last x used returned the same value of x, we cannot improve on that answer.
Amazing that after only 4 interations, I got
x =.337719143 correct to 9 decimal places
Answer This Question
More Related Questions
- Calculus - Find the derivative of y with respect to x. y= (lnx)/(3+4lnx) Should ...
- Math - Find quadratic regressive equation for the following f' points; (x, f'(x...
- Trig - Identies/equation, please help! - 2Sin(Θ+47°)=1 ΘЄ[0°, ...
- Calc - Find the equation of a tangent line of a graph pf y=x^2+4lnx, which is ...
- grammar - hello. is this statement correct in grammar: i think something is ...
- algebra - I need to find the intercepts and then use them to graph the equation...
- algebra (check answers) - 1. what equation represents the following word ...
- Algebra - 2(3x-6)-3(5x+4)=5(7x-8) For this equation, I keep getting ....
- Chemistry - I'm trying do this question: 0.10 mol/L hydrochloric acid is ...
- algebra - how do I find the vertex of y = x^2 - 18? I got -9, -81 but that seems...