# graphs

• Jun 11th 2005, 08:47 AM
slurch901
graphs
can someone please tell me how to plot graphs such as 2x^2 + 10 or something like that cause to be honest it is one my major weaknessess at maths... lol

thx
• Jun 11th 2005, 02:39 PM
Math Help
Graphing equations by hand
$y=2x^2 + 10$

step one determine where the equation crosses the y-axis (when x=0)
$y = 2(0)^2 + 10$
$y = 10$

step two determine where the equation crosses the x-axis (when y=0)
$0=2x^2 + 10$
$-10 = 2x^2$
$\sqrt{-5} = x$, it does not cross the x-axis

Step three determine what shape the equation has
in this case the equation is a parabola that opens upward and is symmetric about the y-axis, therefore its minima is at (0,10)

Play around with a graphing calculator and see what happens to $y = A(x+B)^2+C$ as A, B and C change.