Question 272408: My question is from the Blitzer book, pg 324 #27..
(preset: Use the vertex and intercepts to sketch the graph of each quadratic function. Give the equation of the parabola's axis of symmetry. Use the graph to determine the functions's domain and range.)
#27. f(x) = x^2 - 2x - 3
I cant figure out the domain, thought the range would be (-inf, -3) but the book reads the answer as DOMAIN: (-inf, inf) RANGE: (-4, INF) AXIS OF SYMMETRY: 1
KEY: Inf = Infinity
any help you can give is greatly appreciated. Thanks.
Jay.
Answer by scott8148(6628)   (Show Source):
You can put this solution on YOUR website! the general equation for the axis of symmetry is ___ x = -b / 2a
___ in this case ___ x = -(-2) / (2 (1)) = 1
the domain is the "allowable" values for x ___ ones that don't cause undefined y values (like division by zero)
___ in this case, x can be any real value
the range is values for y resulting from x values put through the function
___ this is a quadratic (parabola)
___ it opens upward (the coefficient of the square term is positive) and has a minimum value (on the axis of symmetry)
___ this minimum value is the lower boundry for the range ___ there is no upper boundry
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