How to graph of a quadratic equation?

:) the teacher gives the students quadratic equation....

Such as, Y = X² + 1

:) start to make a graph of the equation

The process:

1.        1.Determine the intersect point of X_1,2 axis, y=0 by factorization or  ABC formula

Use factorization

Y = X² - 1

(x₁ + 1) (x₂ – 1)

X₁ = -1

X₂ = 1

So, you get the intersect point is (x₁, 0) and (x₂, 0) or (-1, 0) and (1, 0)

2.      2. Determine the intersect point of y_1,2 axis, x=0

    Y = X² – 1 substitute the X to 0

    Y = 0² – 1

       = -1

So, you get the intersect point of y axis is (0, y) or (0, -1)

3.      3. Now, try to sketch the intersect point in the diagram Cartesian

4.    You draw a nicely smooth curving line passing neatly through the plotted points.

5.    After you get the graph. Now,  you should determine the line of symmetry using formula like that X= and determine the extreme point (x , y) = ( , )

6.     The last, you can make the graph of quadratic equation on geogebra, and compare your answer that you get manually and with the geogebra. If the answer is similiar, so the answer is correct.

siti luthfah

2010110029