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OP - What are you trying to do that makes you think you need to ask this question?
Barry has given the answer (which is basic calculus) but I strongly suspect that it is not what you want so you need to tell us more.
(PS Using 'VL' is not very good in this situation as it could be read as 'V*L' which would allow the 'L's to cancel out to a meaningless statement. Given the equation is a very common one, just using 'V' to represent the voltage across the inductor - just as you have used 'I' as the current through the inductor - may have been better.)