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# Warm-Up PowerPoint PPT Presentation

Warm-Up. Visualize a circle and a parabola graphed on the same x-y plane Can you sketch the following scenarios? Zero points of intersection One point of intersection Two points of intersection Three points of intersection Four points of intersection Five points of intersection

Warm-Up

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### Warm-Up

• Visualize a circle and a parabola graphed on the same x-y plane

• Can you sketch the following scenarios?

• Zero points of intersection

• One point of intersection

• Two points of intersection

• Three points of intersection

• Four points of intersection

• Five points of intersection

• What is the maximum number of points of intersection we can have? Why?

Sec 5.1.3

### Learning Targets

• Visualizing End Behavior of Graphs

• Deciphering How Many Solutions There Could/Should Be.

### What is a solution for a system of equations?

• Answer: The solution is where the equations 'meet' or intersect. The red point on the graph is the solution of the system.

• This is where the two equations will produce the same output by using the same input

### How many solutions can a system of linear equations have?

• There can be zero solutions, 1 solution or infinite solutions--each case is explained on the following slide

• Note: Systems of equations can have 3 or more equations, but we are going to refer to a system with only 2 lines.

### What Conclusions can we draw about intersecting lines?

Come up with two conjectures as to what characteristics a system of equations has to have in order for there to be a solution.

What does this say about the importance of the graphs end behavior?

Rate of Change

### P 229, 5-33a

• Solve the following system.

Check the graph.

Check the table.

### P 229, 5-33b

• Solve the following system.

Check the graph.

Check the table.

### P 229, 5-33c

• Solve the following system.

Check the graph.

Check the table.

### P 229, 5-33d

• Solve the following system.

Check the graph.

Check the table.

### Let’s Think About Other Systems

• Now consider the system of equations that consists of a line and a parabola i.e. a linear and a quadratic function.

• Next repeat the process for systems that consist of a two parabolas.

• Repeat the process for systems that consist of a parabola and a circle.

Intersection of a circle and a parabola

### Circle Example

• Consider the following system:

Have many solutions are possible?

The next few slides will display how to use your calculators to solve the system of equations graphically.

Go to slide number 18 to see the steps for algebraic method.

### Graphing Circles on your Calculator as Functions

• A circle is not a function and cannot be graphed in the regular y=screen.

• To graph a circle in the regular y= screen, you have to graph it as two functions on the y= screen.

### Graphing Circles Cont.

First solve the equation of the circle in terms of y.

### Graphing Circles Cont.

Remember a square root can be positive or negative.

In line 1 of y= screen graph what you've been graphing and then graph the same equation in line 2 but with a negative in front of the equation.

You'll get something that looks like an oval since the calculator screen is rectangular.

To make it look more circular (both parts aren't going to connect), press zoom and then select #5 (square).

Choose choice #5 ZSquare

The two parts will not connect

### Graphing the System

Now use the Intersect key to find all points of intersection.

Did you notice both shapes are symmetrical about the

y-axis?

### Algebraic Method

• Rearrange both equations

• Use equal values method.

• Rearrange and solve the quadratic.

• Sub y values into original equations and solve for x.

Final points of intersection:

(-4,3) (4,3) (-3,-4) (3,-4)

### You Solve

y = x2 + 3

x2+ y2 = 9

Use algebra before graphing!

• Review and Preview

• Page 230

• # 37-39, 41-43;

Hint for #42: Equal bases…

### Check in:You Should be Able to use the Following Methods for Solving Systems of Equations

A= Algebraically

G=Graphing