How do I use graph of a quadratic equation like #f(x) = x^2 + 2# to find #f(2)#?

2 Answers
Jul 20, 2018

#f(2)# is putting the value for #x# into the equation. Using the graph - all you do is go to 2 on the #x# axis and read off the #y# value

Jul 20, 2018

#f(2) =6#

Explanation:

#f(x) = x^2+2#

The simplest way to find #f(2)# is to set #x=2# in the function.

#f(2) = 2^2+2 = 4+2 =6#

However, to solve this graphically, you could plot the graph of #f(x)# and the vertical line #x=2#. The solution will then be the intersection of the graphs. As below.

graph{(y-(x^2+2))(0.001y-x+2)=0 [-12.74, 12.59, -2.23, 10.42]}