Sabtu, Desember 06, 2014

Steps To Draw Graph of Quadratic Function

Steps to draw graph of y=ax2+bx+c as follows:
  1. Determine absis intersection, y = 0
  2. Determine ordinat intersection, x = 0
  3. Determine equation of axis of symmetry, x = -b/2a
  4. Determine maximum or minimum value, y = (b2-4ac)/4a
  5. Determine coordinate of extreme point, (x,y) = (-b/2a,(b2-4ac)/4a)
  6. If 5 steps above have not drawn parabola sketch yet, then get some auxiliary point


Example:

Draw graph of equation y=x2-4x-5
  1. Determine absis intersection
    y = 0 then:
    y = x2-4x-5
    (x-5) (x+1) = 0
    x1 = -1 dan x2 = 5
    then absis intersection are (-1,0) dan (5,0)

  2. Determine ordinat intersection
    x = 0 then:
    y = 02-4(0)-5
    y = -5
    then ordinat intersection is (0,-5)

  3. Determine equation of axis of symmetry
    x = -b/2a
    x = -(-4)/2(1)
    x = 2
    axis of symmetry is line x = 2

  4. Determine maximum or minimum value
    y = (b2-4ac)/-4a
    y = ((-4)2-4(1)(-5))/-4(1)
    y = -9

  5. Extreme pointk:
    (-b/2a,(b2-4ac)/4a)
    (-(-4)/2(1),((-4)2-4(1)(-5)/4(1))
    (4/2,36/4)
    (2,9)
  6. Connect points are gotten


Source:
http://lucudankyut.blogspot.com

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