Intersection Points & Finding Unknown Variable

In summary, the equation y=x+k intersects the parabola with equation y=x^2+x−2 at two distinct points if x is not high to the power 1.
  • #1
confusedatmath
14
0
The line with equation y = x + k, where k is a real number, intersects the parabola with equation y = x^2 + x − 2 in two distinct points if

I first made the equations equal each other

x + k = x^2 + x − 2
0 = x^2 -2 -k

From here i thought you use the discriminate a=1 b=o c=-2-k

but this isn't right, because the answer to choose from

k < − 2

k > − 2

k = − 2

k < 2

k ≠ 2
 
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  • #2
confusedatmath said:
The line with equation y = x + k, where k is a real number, intersects the parabola with equation y = + x − 2 in two distinct points if

I first made the equations equal each other

x + k = + x − 2
0 = -2 -k

From here i thought you use the discriminate a=1 b=o c=-2-k

but this isn't right, because the answer to choose from

k < − 2

k > − 2

k = − 2

k < 2

k ≠ 2

Hello.

Check the wording of the question. The parable, need that 'x' is not high to the power 1. (would be a straight line)

Regards.
 
  • #3
mente oscura said:
Hello.

Check the wording of the question. The parable, need that 'x' is not high to the power 1. (would be a straight line)

Regards.
i fixed it :p read again, it was a mistake i forgot the x^2
 
  • #4
confusedatmath said:
The line with equation y = x + k, where k is a real number, intersects the parabola with equation y = x^2 + x − 2 in two distinct points if

I first made the equations equal each other

x + k = x^2 + x − 2
0 = x^2 -2 -k

From here i thought you use the discriminate a=1 b=o c=-2-k

but this isn't right, because the answer to choose from

k < − 2

k > − 2

k = − 2

k < 2

k ≠ 2

Now yes.

[tex]0=x^2-2-k[/tex]

[tex]x^2=k+2[/tex]

[tex]x=\pm{} \sqrt{k+2}[/tex]

1º) [tex]k<-2 \rightarrow{}x \cancel{\in}{R}[/tex]

2º) [tex]k>-2 \rightarrow{}x \in{R}[/tex]

3º) [tex]k=-2 \rightarrow{}x=0[/tex], only a breakpoint.

Regards.
 
  • #5


I can provide a mathematical explanation for the intersection points and finding the unknown variable in this scenario. Firstly, it is important to understand that the line and the parabola intersect at points where their y-coordinates are equal. This can be represented as:

x + k = x^2 + x − 2

Simplifying the equation, we get:

x^2 + x − 2 − (x + k) = 0

x^2 + x − x − 2 − k = 0

x^2 − k − 2 = 0

This is a quadratic equation in terms of x, which can be solved using the quadratic formula:

x = [-b ± √(b^2 - 4ac)]/2a

In this case, a = 1, b = -1, and c = -k - 2. Substituting these values in the formula, we get:

x = [1 ± √(1 - 4(-k-2))]/2

x = [1 ± √(1 + 4k + 8)]/2

x = [1 ± √(4k + 9)]/2

Now, for the line and the parabola to intersect at two distinct points, the discriminant (b^2 - 4ac) must be greater than zero. In this case, it is:

4k + 9 > 0

4k > -9

k > -9/4

Therefore, the correct answer from the given options is k > − 2. This means that for the line and the parabola to intersect at two distinct points, the value of k must be greater than -2.

In summary, as a scientist, I can explain that the intersection points and finding the unknown variable in this scenario involve solving a quadratic equation and using the discriminant to determine the conditions for the two curves to intersect at two distinct points. The value of k must be greater than -2 for the two curves to intersect at two distinct points.
 

FAQ: Intersection Points & Finding Unknown Variable

How do you find the intersection point of two lines?

To find the intersection point of two lines, you can use the method of substitution or the method of elimination. In the method of substitution, you solve one equation for one variable and substitute it into the other equation. In the method of elimination, you manipulate the equations to eliminate one variable and then solve for the remaining variable.

What is the importance of finding intersection points in science?

Finding intersection points is important in science because it helps us understand the relationship between two variables. For example, in physics, finding the intersection point of a position-time graph can tell us the initial velocity of an object. In chemistry, finding the intersection point of two reaction rate graphs can indicate the point of equilibrium.

Can you find the intersection point of more than two lines?

Yes, it is possible to find the intersection point of more than two lines. However, it becomes more complex as the number of lines increases. In this case, it is helpful to use a system of equations and solve for each variable one at a time.

How do you use intersection points to find an unknown variable?

If you have two equations with two variables, you can find the intersection point and use it to solve for the unknown variable. For example, if you have an equation for distance and an equation for time, you can find the intersection point of the two lines and use it to calculate the speed, which is the unknown variable.

Is there a specific method to find intersection points for nonlinear equations?

Yes, there are various methods to find intersection points for nonlinear equations, such as graphical methods, substitution, and numerical methods like Newton's method. It is important to choose the most appropriate method based on the complexity of the equations and the desired level of accuracy.

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