← Back to learning objective

Derivative of a product with e^x combined with a log term

Let g(x)=xex−ln⁡(x2+1).g(x) = x e^x - \ln(x^2+1). Find g′(x)g'(x).

Hint

Differentiate the two terms separately: use the product rule on xexx e^x (with d/dx[ex]=exd/dx[e^x]=e^x), and use the chain rule on ln⁡(x2+1)\ln(x^2+1) (with d/dx[ln⁡u]=u′/ud/dx[\ln u] = u'/u).

Step-by-step solution

For the first term, apply the product rule to xexx e^x: with f(x)=xf(x)=x and h(x)=exh(x)=e^x, we get ddx[xex]=(1)ex+x(ex)=ex+xex\frac{d}{dx}[x e^x] = (1)e^x + x(e^x) = e^x + xe^x.

For the second term, apply the chain rule to ln⁡(x2+1)\ln(x^2+1): the outer function is ln⁡(u)\ln(u) and the inner function is u=x2+1u=x^2+1, so ddx[ln⁡(x2+1)]=1x2+1⋅2x=2xx2+1\frac{d}{dx}[\ln(x^2+1)] = \frac{1}{x^2+1}\cdot 2x = \frac{2x}{x^2+1}. Subtracting this from the first result gives g′(x)=ex+xex−2xx2+1g'(x) = e^x + xe^x - \frac{2x}{x^2+1}.

Related problems

Practice similar Calculus problems interactively.

Start Closing the Gap