How do you find the derivative of 2^x2x?

2 Answers
Apr 6, 2018

d/dx2^x=2^xln2ddx2x=2xln2

Explanation:

In general, the derivative of an exponential with some constant base is

d/dxa^x=a^xlnaddxax=axlna.

A proof of this will be shown.

So, d/dx2^x=2^xln2ddx2x=2xln2

Proof:

Rewrite a^xax as e^ln(a^x)=e^(xlna)eln(ax)=exlna.

Now,

d/dxa^x=d/dxe^(xlna)=e^(xlna)*d/dx(xlna),ddxax=ddxexlna=exlnaddx(xlna), as per the Chain Rule.

We then have

d/dxa^x=e^(xlna)ln(a),ddxax=exlnaln(a), and, recalling that e^(xlna)=a^x,exlna=ax, we finally have

d/dxa^x=a^xlnaddxax=axlna.

Apr 6, 2018

Let y=2^xy=2x

Taking log on both sides,

logy=log2^xlogy=log2x

=>logy=xlog2logy=xlog2

Applying derivative,

=>1/y dy/dx=log21ydydx=log2

=>dy/dx=2^xlog2dydx=2xlog2