Explain why for any constant a, if y = a^x then dy/dx = a^x(ln(a))

So let's start with taking the natural log on both sides of y=ax, giving us ln(y) = ln(ax). Using the laws of logarithms we can write this as ln(y) = xln(a).Next, we differentiate both sides with respect to x, giving d/dx(ln(y)) = d/dx(xln(a)). As the term on the left hand side does not include any x terms we use the chain rule in order to differentiate with respect to y, dy/dx(d/dy(ln(y)) = d/dx(xln(a)) and then carry out the differentiation. We are then left with dy/dx(1/y) = ln(a), and, using some manipulation we find dy/dx = yln(a), and the original substitution leaves us with exactly what we're looking for y = ax(ln(a)).

JM
Answered by James M. Maths tutor

10884 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Integrate sin^2(x) with respect to x


Integrate (x+3)/(x(x-3)) with respect to x


Show that the integral ∫(1-2 sin^2⁡x)/(1+2sinxcosx) dx = (1/2) ln2 between the limits π/4 and 0. [5 marks]


The points A and B have coordinates (1, 6) and (7,− 2) respectively. (a) Find the length of AB.


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences