# Thread: differention (equation of tangent)

1. ## differention (equation of tangent)

Using differentiation find the equation of the tangent to the curve
y= 4 + ln(x+1) at the point where x=0

Thanks!

2. Originally Posted by Oasis1993
Using differentiation find the equation of the tangent to the curve
y= 4 + ln(x+1) at the point where x=0

Thanks!
Have you found the derivative of 4+ ln(x+1)?

3. i think im doing the mistake there.
is the derivative of y= 4+ ln(x+1) 1/(x+1) or 4/ (x+1) ?

4. Originally Posted by Oasis1993
i think im doing the mistake there.
is the derivative of y= 4+ ln(x+1) 1/(x+1) or 4/ (x+1) ?
Neither. The derivative of "4" is "0" and the derivative of "ln(x+1)" is " $\frac{1}{x+1}$". The derivative of the sum f+ g is f'+ g' so the derivative of 4+ ln(x+1) is $0+ \frac{1}{x+1}= \frac{1}{x+1}$.

5. yes the derivative of the equation is 1 / (x+1).
But what do i do to get the equation of the tangent?
I put 0 instead of x which gives 1?..and then?

6. The first thing you should have learned about the derivative is that it generalizes the slope of a line.

The slope of the tangent line to a curve at a point is the derivative at that point.