thats what ive done:
x cant be 3 and 2
x²-4x+4/x-3×(x-3)²>0
(x²-4x+4)×(x-3)>0
y=(x²-4x+4)(x-3) y>0
now i'll open the brackets:x³-3x²-4x²+12x+4x-12=x³-7x²+16x-12
so how is going to look the parabola?
Thanks Chris, Sabi and Dragonlance,
I'll just put my 2 bob's worth in :)
$$\\\frac{x^2-4+4}{x-3}>0\\\\
\frac{(x-2)^2}{x-3}>0\\\\
x\ne 3\\\\
\frac{(x-2)^2}{x-3}\times (x-3)^2>0\times (x-3)^2\\\\
(x-2)^2(x-3)>0\\\\
consider\;\; y=(x-2)^2(x-3)\;\;\\\\$$
You are right Sabi this is not a parabola but it is a polynomial - (a parabola is a polynomial of degree 2)
When will the graph be above the x axis?
There is a root at x=3, and a double root at x=2.
The highest power of x is 3 That is the degree of this polynomial is 3.
This means that the graph will have 3 directions.
I can immediately see that the coefficient is X^3 is 1. i.e. The leading coefficient=1.
A positive leading coefficient means that the graph will finish in the top right hand corner.
So I know a lot about how this graph will look, just by a cursory examination of the formula.
I know that it will look like this!
I can see from the graph that this is greater than 0 when x>3
---------------------
I wrote this post some time ago, I just fished it out of our reference material sticky topics.
It would be a very good idea for you to try and make sense of it all.
I have done the top row of graphs, maybe you would like to take a look at the bottom row :))
http://web2.0calc.com/questions/how-do-you-find-a-power-function-that-is-graphed
Here's the way I like to approach this kind of problem....
Solve for the top and bottom separately....
Set the top = 0 and factor....we have.... x^2 - 4x + 4 = 0 → (x - 2)^2 = 0 so x =2
Do the same for the bottom
x - 3 = 0 so x = 3
Now.....plot these two values on a number line......neither will be part of the answer (because of the > sign), but the answer(s) will come from one or more of these intervals.....
(-∞, 2), (2, 3) or (3, ∞)
Pick a number in the first interval....0 seems nice ....put it nto the original problem.....does it make it true??...Nope
Pick a number in the middle interval...say 2.5......you will find this doesn't work, either
Finally.....pick a number in the last interval, say 4.....you will find that this is the only interval that solves this problem
Here's a graph.....https://www.desmos.com/calculator/talcaantp7
Note that the original problem is only greater than 0 on the specified interval
CPhill a question.
You set x= 3 and that makes the fraction divided by zero. I thougt that was not allowed for solving equations. Is it because it is ploted on the the graph and the line dissapears or goes to infinity when x=3 that it is allowed?
Thats how i solved it(according to your recommendation to solve the top and bottom separately:
first of all:a≠2,3
x²-4x+4>0 x²-4x+4<0
and or and
x-3>0 x-3<0
⇓ numenator:x²-4x+4=0 ⇓
(x-2)²=0
x=2
x ≠2 no x
x-3>0 denominator:
x>3 x<3
so the answer:x>3
Remember, Dragonlance, x = 3 isn't a part of the solution.......I'm just doing this to find the interval points.......the solution is x > 3 as sabi92 found .... or....as I gave ..... (3, ∞ )......both of these are the same solutions
Thanks Chris, Sabi and Dragonlance,
I'll just put my 2 bob's worth in :)
$$\\\frac{x^2-4+4}{x-3}>0\\\\
\frac{(x-2)^2}{x-3}>0\\\\
x\ne 3\\\\
\frac{(x-2)^2}{x-3}\times (x-3)^2>0\times (x-3)^2\\\\
(x-2)^2(x-3)>0\\\\
consider\;\; y=(x-2)^2(x-3)\;\;\\\\$$
You are right Sabi this is not a parabola but it is a polynomial - (a parabola is a polynomial of degree 2)
When will the graph be above the x axis?
There is a root at x=3, and a double root at x=2.
The highest power of x is 3 That is the degree of this polynomial is 3.
This means that the graph will have 3 directions.
I can immediately see that the coefficient is X^3 is 1. i.e. The leading coefficient=1.
A positive leading coefficient means that the graph will finish in the top right hand corner.
So I know a lot about how this graph will look, just by a cursory examination of the formula.
I know that it will look like this!
I can see from the graph that this is greater than 0 when x>3
---------------------
I wrote this post some time ago, I just fished it out of our reference material sticky topics.
It would be a very good idea for you to try and make sense of it all.
I have done the top row of graphs, maybe you would like to take a look at the bottom row :))
http://web2.0calc.com/questions/how-do-you-find-a-power-function-that-is-graphed