Use the definition of the derivative (don't be tempted to take shortcuts!) to find the derivative of the function f(x)=3−5x6+9x. Then state the domain of the function and the domain of the derivative. Note: When entering interval notation in WeBWorK, use I for [infinity], -I for −[infinity], and U for the union symbol. If the set is empty, enter "{}" without the quotation marks.

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.