Question

diffrencial of logex is what . . .?

Answer 1

7 answers · Mathematics
Best Answer
If you're learning about the derivative of logs, then by now, you should know (and preferably be reasonably comfortable with) the chain rule and the product rule (quotient rule doesn't hurt either). These rules are critical to breaking down almost every elementary function you can find into simple parts that you can differentiate. So, when your teacher tells you that d/dx ln x = 1/x, she's hoping that it will be part of a larger repertoire, so that you can start differentiating complicated expressions involving logs.

I could help you now, but there's clearly some problems in the fundamentals here; something you can't fix overnight with Y!A. If you need some special help, ask your teacher for some personal help, or find a tutor. That may be the one piece of maths help you'll ever need!

If you need a bandaid help now, then you can use the following rule:

If y = ln(f(x))
then y' = f ' (x) / f(x)

This comes easily from the chain rule. For example:

y = ln(3x + 7)

In this case, f(x) = 3x + 7. We can see easily that f ' (x) = 3. So:

y' = f ' (x) / f(x) = 3 / (3x + 7)