F(x) = 2x2 + 5x + 20 Find f(-9)
2 answers:
You might be interested in
Answer:
Step-by-step explanation:
Given that a rectangle is constructed with its base on the x axis and two of its vertices on the parabola
This parabola has vertex at (0,100) and symmetrical about y axis.
Any general point above x axis can be written as (a,b) (-a,b) since symmetrical about yaxis.
Hence coordinates of any rectangle are
Length of rectangle = 2a and width =
Area of rectangle = lw =
To find max area, use derivative test.
Hence maxima when first derivative =0
i.e. when a =2
Thus we find dimensions of the rectangle are l =4 and w = 96
Maximum area =