Question
Find the critical points of f(x) = 0.05x + 25 + (180/x)
Answers
Reiny
x-intercepts, let y = 0
.005x + 25 + 180/x = 0
,005x^2 + 25x + 180 = 0
x = (-25 ± √621.4)/.1
= appr -.721 or -499.28
y-intercepts, let x = 0
y = undefined, there is no y-intercept
dy/dx = .05+0-180/x^2
= 0 for max/min
.05 = 180/x^2
x^2 = 3600
x = ± 60
plug in to find the corresponding y values
.005x + 25 + 180/x = 0
,005x^2 + 25x + 180 = 0
x = (-25 ± √621.4)/.1
= appr -.721 or -499.28
y-intercepts, let x = 0
y = undefined, there is no y-intercept
dy/dx = .05+0-180/x^2
= 0 for max/min
.05 = 180/x^2
x^2 = 3600
x = ± 60
plug in to find the corresponding y values