Thread: Another derivative problem

I have problems with finding derivatives using the definition of a derivative when there are square roots involved for some reason. I'm trying to find the derivative of 1/sqrt b and keep getting the same wrong answer, could someone set me straight about how to approach such a problem?

You would look at it like:



As a square root has an exponent of (1/2), and it being in the denominator makes it negative. From there, it's simple:



or




If you mean the limit definition, then:



as delta-b approaches 0.

&



so:




And then the (-1/2) exponents kind of lose me. Sorry. I feel dumb but I don't remember doing this.

thanks that actually cleared it up quite a bit for me.

Alright then!

I have no clue what to do there really, or at least I'm really tired.