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)).

Answered by James M. Maths tutor

9101 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Express (x+1)/2x + (2x+3)/(x+1) as one term


Differentiate the following equation with respect to x; sinx + 3x^2 - 2.


Find the minimum value of the function, f(x)= x^2 + 5x + 2, where x belongs to the set of Real numbers


A curve is described by the equation (x^2)+4xy+(y^2)+27=0. The tangent to the point P, which lies on the curve, is parallel to the x-axis. Given the x-co-ordinate of P is negative, find the co-ordinates of P.


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2024

Terms & Conditions|Privacy Policy
Cookie Preferences