How do you graph #f(x) = -x^2 + 2x - 4 #?

1 Answer
Nallasivam V
Aug 30, 2015

Refer explanation section.

Explanation:

Given -
y = #-x^2 + 2x -4#

It is a U shaped curve. Since the sign of the #x^2# is negative, it is concave downwards.

Find the vertex -

x = #(-b)/(2a) = (-2)/ (2 xx (-1))# = 1

It means when x takes the value 1, the curve turns.
Take a few values on either side of 1. Calculate corresponding y values. Plot the pairs. Join them with the help of a smooth curve

x : y
-2 : -12
-1 : -7
0 : -4
1 : -3
2 : -4
3 : -7
4 : -12
graph{-x^2 +2x -4 [-11.79, 8.21, -8.76, 1.24]}

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