How to use your graphing calculator ..

Okaaaay. Getting back into the groove of things, let's get this blog going again.

Today, our new unit. ALGEBRA

What we basically did today was learn four different ways to use our calculators to find the roots (zeros or x-intercepts, whichever you prefer) of an equation.

The equation we are given is : 6 = x^2 + 6x + 11 (quadratic function)
0 = x^2 + 6x + 5 (standard form of the function)
*this is the equation we will be using for ALL the examples*

TRACE METHOD
step 1) Graph the related equation (standard form of the function)
step 2) Press the " Y= " button, and enter the quadratic function.
step 3) Have your " WINDOW " settings set to:
Xmin = -9.4
Xmax = 9.4
Ymin = -9.4
Ymax = 9.4
step 4) Press, " GRAPH ", " TRACE " and find X when y = 6. Use the left and right arrow keys to trace the graph.

ZERO FUNCTION METHOD
step 1) Graph the standard form of the function, by pressing the " Y= " button, and then entering the standard form.
step 2) Press " 2nd " then " CALC " and select " 2: Zero "
step 3) Guess values for the left and right boundaries. It has to be about 2 units less than the point on the left side of the x-axis, and about 2 units more than the point on the right side of the x-axis.
step 4) Select guess.

EQUATION SOLVER METHOD
step 1) Press " MATH " and pick " 0: Solver "
step 2) Press the up arrow key to clear the equation on the screen, a new screen should appear.
step 3) Press " CLEAR " to erase the equation beside the " 0 = "
step 4) Enter the standard form beside " 0 = " and press " ENTER "
step 5) Enter a number next to " x = " that is less than a possible x-intercept. So, in this case, you'd enter -2, due to the fact that -1 > -2.
step 6) Press " ALPHA " then " ENTER. " Round your answer.

COMPARING METHOD
step 1) Graph the quadratic function, and also graph " y = 6 "
step 2) Find the intersection (where they meet) point of the graphs.
step 3) Repeat for the standard form and " y = 0 "
step 7) Repeat on the opposite side.

Note: Your zeros should all end up to be x = -1 and x = 5

I know, it's a little tricky, but trust me, try the equations on the last page of the handout, and you'll get the hang of it.

That's it for me, later.

- Jho