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Here are a few recommended readings before getting started with this lesson.
Determine if the given system of equations is nonlinear or linear.
A system of equations does not necessarily consist of linear equations. Different types of equations can be grouped into a system.
For every given system of equations shown in the applet, determine if the system is a system of quadratic equations or not. Note that every equation in such a system needs to be a quadratic equation.
Another type of non-linear system is a quadratic-quadratic system, which consists of two quadratic equations. These systems can have zero, one, two, or infinitely many different solutions. These solutions are the points of intersection of the graphs.
Graphing the equations of a system of equations is helpful. Sometimes it is even possible to solve the system by referencing the graph only.
The first equation of the nonlinear system is a linear equation written in slope-intercept form. By using the slope of and the intercept of the equation is graphed in a coordinate plane.
Then, the second equation needs to be graphed.
Then, the intercept is the value of of the equation, which in this case is Since the axis of symmetry divides the graph into two mirror images, the parabola also goes through point in
Using these points, it is possible to draw the parabola.
Finally, finding the points in which the graph intersect, the solutions of the nonlinear system are found.
This means that the points and are the solutions of the nonlinear system.
Emily received a scholarship this summer and attended a camp for skydiving. She has always dreamed of feeling like flying in the sky. Surprisingly, her first task given by her instructor Sky Flyer is to solve a nonlinear system graphically.
Graph both equations and find the points of intersection.
The value of on a quadratic equation written in standard form indicates the value of the intercept. In this case, the value of the intercept is Since the axis of symmetry divides the graph into mirror images, the points and can be added.
These points can be used to graph the parabola.
Looking at the graph, the points of intersection can be located.
The solutions of the nonlinear system are the points and
Instructor Sky Flyer continues teaching Emily about nonlinear systems. Emily is unsure but thinks they must be getting closer to applying this knowledge to something spectacular.
How do you find the axis of symmetry of a parabola if the quadratic equation is written in standard form?
To solve a quadratic-quadratic system graphically, both quadratic equations are graphed to identify the points of intersection. Looking at the system, it can be noted that both equations of the system are written in standard form.
It is possible to find the intercept of the parabola with the value of In Equation (I), this value is Also, since the axis of symmetry mirrors the image of the parabola, there is another known point at These points can be used to graph the parabola.
The value on Equation (II) indicates that the intercept of the second parabola is Since the axis of symmetry mirrors the image, there is another known point
Now that the two equations are graphed, the solutions of the nonlinear system can be determined. They are the points of intersection of the graphs.
The points and are the solutions of the nonlinear system.
Just like in a system of linear equations, there are many methods that can be used to solve a nonlinear system.
Use the Quadratic Formula:
Calculate power
Multiply
Add terms
Calculate root
Therefore, the values of that solve the nonlinear system are and
Now that there are two known values for the solution values for can be found by substituting the values of into either equation. Since Equation (II) is linear, it is easier to do so in this equation.
Combining each value value with its correspondent value, it can be seen that the solutions can be written as the points and
Which variable is the easiest to eliminate?
The two possible values for are about seconds and about seconds. Only positive numbers make sense in this case since the skydiver cannot wait a negative time before releasing the parachute. This means that the jumper waited about seconds to release the parachute.
Before having the chance to skydive, Instructor Sky Flyer wants to show how the students can train by practicing acrobatics. They all walk into a large gym to see a few pros practice. One acrobat jumped from a platform, and another dove from another higher platform just a split second later. Mid-air, they did a high-five while spinning!
Substitute values
Calculate power
Multiply
Add terms
Calculate root
To find the values of the values of and are substituted into either equation of the system. It is easier to substitute the values into Equation (II) because it is a linear equation, instead of quadratic.
This indicates that the solutions of the system are the points and
Finally, all the math and practice is making sense. Emily is now ready for her first jump! Instructor Sky Flyer prepared an equation to record Emily's height above the ground.
The time after Emily jumps has to be positive. Because of this, the only solution that makes sense is the positive one. Therefore, Emily released her parachute about seconds after she jumped.
As Emily is on cloud nine after skydiving, she dreams of making a formation with other skydivers, where the skydivers make two intersecting circles.
She then realizes that Instructor Sky Flyer would tell her to solve a nonlinear system.
Isolate a term of one equation to substitute into the other one.
Finally, these values are substituted into Equation (II) to find the values of of the points of intersection.
The points of intersection are and
Substitute values
Calculate power
Multiply
Add terms
Calculate root