## Polynomial Rectangles with a common factor

Posted: December 8, 2015 in factoring, math education, polynomial factoring, quadratic, visual mathTags: GCF, grid factoring, polynomial rectangles

## Three Related Polynomial Rectangles

Posted: December 8, 2015 in factoring, math education, polynomial factoring, quadratic, visual mathTags: difference of squares, grid multiplication, perfect square

One of my students posted this example of a vertical stretch and wrote the words “wider and taller”…and I said, “wait a sec!”

Usually a vertical stretch makes the graph look taller and “thinner”; but, when I thought about this, it seems that we usually look at graphs where the curves face inward (toward the axis of symmetry or some other center-ish axis). I am thinking of a parabola, a cubic, or a sinusoidal function. Here however, the curves open away from the center and thus the vertical stretch gets wider.

## Using parabolas to paint a picture

Posted: April 10, 2015 in design, parabola, quadratic, rainbowTags: graphing calculator

Notice how some equations are written in vertex form, others are in standard, and others are in factored form. Bravo, Paige!

## Graphing a Heart on Your Graphing Calculator

Posted: February 13, 2015 in UncategorizedTags: graphing calculator, valentine math

Here are the functions that will graph a heart in a window with an x-max is 10, x-min is -10, y-min is -7, y-max is 7). To input the forward slash use the divide key and to input the inequality signs, press 2nd Math. To use this as a learning opportunity, reflect on how one might graph a circle and a line and how I used these to make a heart. Also, in the curly brackets, I have restricted the domain of the semi-circles and the lines. Think about what you know about domain restrictions and how this is working here. To see the effect of the domain restrictions, try viewing the graph without the domain restrictions.

**Math 30-1** students, ask yourself how I used transformations of a circle to make the first four functions. Look below to understand better how to graph a circle.

**All students**: compare the Pythagorean Theorem to the functions that graph a circle. A semi-circle with radius 3 can be graphed with y=sqrt(9-x^2) which comes from 3^2=x^2 + y^2. Check out some youtube videos about how to graph a circle (a set of points equidistant from a given point.

**More for All**: can you graph an arrow through this heart using y=mx+b? Happy Valentines, everyone.

**Challenge**: Can you figure out how to get rid of the extra bits of line at the bottom? Or can you adjust the window so that the lines are only visible where you want them.

## Why do we teach math differently in 2014 than we did in 1980?

Posted: November 25, 2014 in UncategorizedThis video, the first in a series from the Hypotenmoose Kitchen, will guide you to build a paper kit from which we can learn much about fractions.

## My True Love: Using Visualization as a Tool to Think With

Posted: December 17, 2013 in factoring, family math, on-line learning, polynomial factoring, Uncategorized, visual mathIn the last week before winter break, it is tempting to let the curriculum go a little, to kick back and enjoy my students without my mathematical lens. **NOT!** For me, there is much more pleasure in going deeper into curriculum. If there is something to let go of, it is the “schoolishness” of some math that we do. In the video below, I was able to revel in one of my favorite topics: factoring polynomials. This method, based on thinking of products as area and factors as dimensions, was taught to me by Dr. Tom Kieren, an exceptional scholar and educator.

I would like to see this kind of factoring in all our high school classrooms. It demonstrates three features of a well chosen algorithm: transparency, error resistance, and memorability.

## Advent Calendar filled with math activities!

Posted: December 6, 2013 in family math, holiday math, on-line learningWhat could be better than a challenging math activity each day of December! I wish I could have embedded it here, but alas, this link will have to do.

This one is for Secondary Students: http://nrich.maths.org/10472.

And this one is for Primary: http://nrich.maths.org/10473.

These are great launching pads for parent/child interaction.