Find the derivative of 1 / square root of 2x
from first principles.
hellp !
xx
when you see "from first principles" they are talking about using the definition of the derivative.
there are two (equivalent) definitions:
if this is the definition you have been taught, then you are required to find the limit
alternatively, you may use the definition
in this case you are required to find the limit
(and replace with when finished)
Notation: and mean "the derivative of (with respect to )" and "the derivative of (with respect to x) at the point " respectively.
here of course,