Need help in solving this question about a rational inequality

In summary, the conversation discusses finding the range of the function x/(x^2+x+1) and the application of the condition that Determinant(D)>=0 to solve the problem. The function is bounded by a and b, approaches zero for large or very negative x, and has both a maximum and minimum value. This problem can be solved using techniques from calculus to find the two extreme points.
  • #1
navneet9431
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Homework Statement


IMG_20180823_100953.jpg

Go through question number 4

Homework Equations


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The Attempt at a Solution


See basically the question is asking us to find the range of the given function x/(x^2+x+1).
So,I began solving it this way...
IMG_20180823_101557.jpg

I am stuck at this step.
I asked my friend for a hint and he told me to apply the condition that Determinant(D)>=0.
But,I am unable to understand why D>=0?
I will be thankful for help!
 

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  • #3
The function that is bounded by a and b is ##f(x) = \frac x {x^2 + x + 1}##. For large x or very negative x, f(x) approaches zero. The function is continuous everywhere, and has both a maximum and minumum value. You have posted this question in the Precalc section, but the problem is one that can be solved using techniques from calculus, to find the two extreme points.

BTW, in your thread title, you described this as a problem about a polynomial equation, which it isn't. I've edited your title so that it is about a rational inequality.
 
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Likes jedishrfu

1. What is a rational inequality?

A rational inequality is an inequality with one or more rational expressions involving variables in the numerator and denominator.

2. How do I solve a rational inequality?

To solve a rational inequality, you need to follow these steps:
1. Simplify both sides of the inequality if possible.
2. Find the critical values by setting the denominator equal to zero and solving for the variable.
3. Use the critical values to create intervals on a number line.
4. Test a value in each interval to determine if it satisfies the original inequality.
5. Write the final solution using interval notation.

3. Can I use the same methods for solving rational equations to solve rational inequalities?

Yes, the methods for solving rational equations can also be used to solve rational inequalities. However, when multiplying or dividing both sides of the inequality by a negative number, the direction of the inequality sign must be flipped.

4. What are the common mistakes when solving rational inequalities?

Some common mistakes when solving rational inequalities include:
- Forgetting to flip the inequality sign when multiplying or dividing by a negative number.
- Not simplifying the rational expressions before solving.
- Forgetting to include the solution to the critical values in the final answer.

5. Can I graph a rational inequality to solve it?

Yes, you can graph a rational inequality to help you solve it. The solution to a rational inequality is represented by the shaded region on the graph. However, it is still important to follow the steps for solving algebraically to ensure accuracy.

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