A looks good
points in A are max/min if y" is negative/positive
y is increasing if y' > 0
inflection where y" = 0
1) For the function 𝑦(𝑥) = 𝑥^3 − 3𝑥^2 − 9𝑥 + 5
a) Find the critical points.
b) Determine if the critical points are maximum or minimum.
c) Determine the interval where the given function is increasing and/or decreasing.
d) Find any points of inflection.
My answers:
a) 𝑦(𝑥) = 𝑥^3 − 3𝑥^2 − 9𝑥 + 5
y'(d)=d/dx (𝑥^3 − 3𝑥^2 − 9𝑥 + 5)
y'(x)= 3x^2 - 3*2x - 9 +0
y'(x) = 3x^2 - 6x -9
3x^2 - 6x -9 = 0
3 (x^2 - 2x -3)=0
x^2 - 2x -3 = 0
(x+1)(x-3)=0
x=1 and x= -3 are the critical points
can someone check my answer for part A and help me for B, C and D.
1 answer
1 answer