Chapter 3: Problem 11
Find the derivatives of the given functions. Assume that \(a, b, c,\) and \(k\) are constants. $$y=x^{-3 / 4}$$
Short Answer
Expert verified
The derivative is \(\frac{dy}{dx} = -\frac{3}{4} x^{-\frac{7}{4}}\).
Step by step solution
01
Identify the Power Rule for Differentiation
The function given is in the form of a power function, where the general power rule for differentiation is \ \( \frac{d}{dx} x^n = nx^{n-1} \). Identify the exponent in the given function to apply this rule correctly.
02
Apply the Power Rule
The given function is \ \( y = x^{-3/4} \). Here, \ \( n = -\frac{3}{4} \). Using the power rule, the derivative of \ \( y \) with respect to \ \( x \) is: \[ \frac{dy}{dx} = \left( -\frac{3}{4} \right) x^{-\frac{3}{4} - 1} \]
03
Simplify the Expression
Now simplify the expression obtained from the application of the power rule. The exponent \ \( -\frac{3}{4} - 1 \) becomes \ \( -\frac{3}{4} - \frac{4}{4} = -\frac{7}{4} \). Therefore, the derivative is:\[ \frac{dy}{dx} = -\frac{3}{4} x^{-\frac{7}{4}} \]
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Power Rule for Derivatives
The Power Rule is a simple yet powerful tool in calculus that makes finding derivatives of power functions a breeze. It states that if you have a function of the form \( f(x) = x^n \), the derivative with respect to \( x \) is determined using the formula \( \frac{d}{dx} x^n = nx^{n-1} \). This means you take the exponent \( n \) down as a coefficient in front of the variable and then subtract one from the exponent.
- Example: If \( y = x^{-3/4} \), to find the derivative, you identify \( n = -3/4 \).
- The derivative is \( \frac{dy}{dx} = -\frac{3}{4} x^{-3/4 - 1} = -\frac{3}{4} x^{-7/4} \).
Differentiation
Differentiation is a core concept in calculus, dedicated to finding how a function changes as its input changes. In basic terms, it gives us the slope of a tangent to the curve of the function at any point. This is crucial for analyzing functions, calculating rates of change, and in many practical applications like physics and economics.For a function \( y = f(x) \), the process of differentiation yields its derivative \( \frac{dy}{dx} \), which shows the rate of change of \( y \) with respect to \( x \). When using the power rule, differentiation becomes much simpler, especially for polynomial functions.
- To differentiate \( y = x^{-3/4} \), apply the power rule: bring down the exponent as a coefficient, and reduce the exponent by one.
- The new expression \( -\frac{3}{4}x^{-7/4} \) represents the change in \( y \) with every tiny change in \( x \).
Exponent Rules in Calculus
Understanding exponent rules is crucial when dealing with differentiation, especially when applying the power rule. Exponents dictate how a quantity grows and are often expressed in polynomial functions you encounter in calculus. When differentiating functions with exponents, like our example \( y = x^{-3/4} \), you'll need to manipulate exponents accurately.Key exponent rules include:
- Product of powers: \( x^a \times x^b = x^{a+b} \)
- Quotient of powers: \( \frac{x^a}{x^b} = x^{a-b} \)
- Power of a power: \( (x^a)^b = x^{ab} \)