a) when x=e^2, y = lne^2/e^2 = 2/e^2 and
y' = (1-lne^2)/e^4 = -1/e^4
so the equation is x + (e^4)y = c
but (e^2,2/e^2) lies on it, so
e^2 + e^4(2/e^2) = c
c = 3e^2
the equation is x + (e^4)y = 3e^2
( I am using a quick way to find the equation of a line based on the fact that if the slope is -A/B, then the equation is Ax + By = C )
b) set f'(x) = 0
(1- lnx)/x^2 = 0
1 - ln x = 0
ln x = 1
x = e then y = ln e/e = 1/e
the critical point is (1,1/e)
To determine if it is a max/min I will do c) first
c) for f''(x) I got
(-3 + 2lnx)/x^3
setting that equal to zero ...
2lnx = 3
lnx = 3/2
x = 4.4817 and y = .3347
so there is a point of inflection at (4.48,0.33)
Back to b)
when you plug x=e^2 into f'' you get
(-3+ 2lne^2)/e^6 which is positive.
Therefore the critical point from b) is a minimum point of the function.
Math - Given the axioms: ln x = definite integral from 1 to x of 1/t dt ln e = 1...
Calc - a) y =ln(x-1) find dy/dx=? b) y=3 ln x - ln (1/x) where x >0, dy/dx...
Pre-Calc - I am stuck solving this problem, any help please..Many thanks find ...
Pre-calc Solve logarithmic - ln sqrt(x-8)= 5 I would like help to solve this ...
Alegebra2 - 1. Given f(x)=3^(x-2), simplify f(x+1)-f(x) into an expression of ...
Math - ln x^2(x+1)/x+2 Write in terms of ln(x), ln(x+1), and ln(x+2) is the ...
Maths - Expand ln(1+x) and ln(1-x) and hence deduce that ln((y+1)/(y-1))=[2/y]+[...
Calc - Find an equation of the tangent line to the graph of the function at the ...
Maths - Solve the given equation: ln(x + 4) + ln(x + 2) = 2 ps - we aren't ...
math - Express y as a function of x. C is a positive number. 3 ln y= 1/2ln (2x+1...