Topics:
• Completing the square to put the equation of a circle into its standard form
• Brief review of solving a system of 2 linear equations in 2 variables by elimination
• Solving a system of 3 linear equations in 3 variables
The two outline notes pages which I handed out in class are also available here:
There is a very nice video explaining this method at Patrick’s Just Math Tutorials. He explains the reasoning along the way.
There is a longer video explanation of the method along with background information about 3 by 3 systems at Khan Academy.
Homework:
• Review completing the square for the equation of a circle. Make sure also that you know how to read off the center and vertex of the circle, how to find four points on the circle from that information, and how to use them to draw the graph of the circle.
Free graph paper that you can print out is available from many sources online, for example at Print Free Graph Paper. This is very helpful in making sure that your graphs really do look like circles!
• Review solving 2 by 2 systems of linear equations by elimination. You should know how this method works, and also be aware which variable it is that you are eliminating. We need to know that when we apply elimination to solving a system of 3 equations in 3 variables!
• Finish working the handout (the 3 by 3 system) if you did not have time to do this in class. Make sure to check your answer by substituting back into all three equations! If you get stuck on this, please post a question to Piazza, and in your question post a clear photo of the work you did.
• Do the WeBWorK: start as soon as possible to do a bit of it, and do distributed practice!
• From the textbook, do the following problems: pp. 753-754 #39-47 odd; p. 286, #11, 13, 15. When you solve the 3 by 3 systems of equations, don’t forget to check your solutions by substituting back in all three equations.
Remember that you can use the Piazza discussion board to ask questions if you get stuck on any of the WeBWorK or the other homework problems. Don’t forget to include the problem itself in your question, as that will make it easier for you to get a quick response!
