Chapter 3: Problem 7
Find the derivative. Assume that \(a, b, c,\) and \(k\) are constants. $$y=x \ln x$$
Short Answer
Expert verified
The derivative is \( \ln x + 1 \).
Step by step solution
01
Identify the Function
We are given the function \( y = x \ln x \). This function is a product of two functions: \( u(x) = x \) and \( v(x) = \ln x \).
02
Apply the Product Rule
The product rule states that the derivative of a product of two functions \( u(x) \) and \( v(x) \) is \( u'(x)v(x) + u(x)v'(x) \). Here, apply the rule to find \( \frac{d}{dx}[x \ln x] \): - \( u(x) = x \), so \( u'(x) = 1 \) - \( v(x) = \ln x \), so \( v'(x) = \frac{1}{x} \).
03
Substitute and Simplify
Substitute the derivatives back into the product rule formula:\[ \frac{d}{dx}[x \ln x] = u'(x)v(x) + u(x)v'(x) = 1 \cdot \ln x + x \cdot \frac{1}{x} \] Simplify the expression:\[ \frac{d}{dx}[x \ln x] = \ln x + 1 \]
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Product Rule
The product rule is a core principle in calculus, specifically useful when we're dealing with the derivative of a product of two functions. In simple terms, when you have two functions multiplied together, like in our exercise with \(y = x \ln x\), the product rule helps us find the derivative of this product. To apply the product rule, follow this straightforward formula: if we have two functions \(u(x)\) and \(v(x)\), the derivative \(\frac{d}{dx}[u(x)v(x)]\) is given by
- \(u'(x)v(x)\) + \(u(x)v'(x)\)
Differentiation
Differentiation is the process of finding a derivative. A derivative represents how a function changes as its input varies, essentially capturing its rate of change. In the context of our exercise, we're using differentiation to find how the function \(y = x \ln x\) changes with respect to \(x\).
- The first task is to identify the functions involved. Here, we have \(u(x) = x\) and \(v(x) = \ln x\).
- For differentiation, compute the derivatives: \(u'(x) = 1\) and \(v'(x) = \frac{1}{x}\).
Natural Logarithm
The natural logarithm, denoted as \(\ln x\), is a logarithm with the base \(e\), where \(e\) is a mathematical constant approximately equal to 2.71828. The natural logarithm has several unique properties that make it particularly useful in calculus and mathematical analysis.
- The derivative of \(\ln x\) is \(\frac{1}{x}\), which plays a crucial role in our exercise when applying the product rule.
- It's commonly used in the study of exponential growth and decay, financial models, and complex calculus problems.
- In the expression \(y = x \ln x\), the \(\ln x\) component helps describe logarithmic growth or scaling relative to \(x\).