Thread: Differentiating exponential and logarithmic functions

1. Differentiating exponential and logarithmic functions

Determine the equation of the tangent to the graph of y=log(lnk).

1/(lnkln10)

just can someone confirm this plz

2. Your solution for the equation of the tangent line is correct. The $x$-intercept is the value of $x$ when $y=0$. In our case,

$0=kx_0+\ln\frac{1}{k}-1.$

Hope this helps!

3. so then how do i solve for k?

4. because the x is there

5. Originally Posted by john-1
so then how do i solve for k?
hi

kx - ln k -1=0

$x=\frac{1+\ln k}{k}>0$

so k would be k<0 or k>1/e

but k<0 is not acceptable because ln (<0) is undefined .

Do the same to determine the set of values of k so that x is negative .