Chapter 1: Problem 46
Find \(f^{\prime}(x)\). $$f(x)=-0.01 x^{2}+0.4 x+50$$
Short Answer
Expert verified
-0.02x + 0.4
Step by step solution
01
- Identify the function
The given function is: \[ f(x) = -0.01 x^{2} + 0.4 x + 50 \] This is a quadratic function.
02
- Apply the power rule for differentiation
To find the derivative, use the power rule which states that for any term of the form \( ax^n \), the derivative is \( n \times ax^{n-1} \).
03
- Differentiate each term
Differentiate each term of the function individually: \[ \text{First term: } -0.01 x^{2} \rightarrow -0.01 \times 2 \times x^{2-1} = -0.02 x \] \[ \text{Second term: } 0.4 x \rightarrow 0.4 \times 1 \times x^{1-1} = 0.4 \] The constant term 50 has a derivative of 0.
04
- Combine the derivatives
Combine the differentiated terms to get the final result: \[ -0.02 x + 0.4 \]
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Quadratic Functions
Quadratic functions are a type of polynomial function where the highest degree term is squared. For example, in the function \(f(x)=-0.01x^2 + 0.4x + 50\), the term \(-0.01x^2\) is the quadratic term.
This function can be written in the general form \(ax^2 + bx + c\), where:\
If \(a\) is positive, the parabola opens upwards, and if \(a\) is negative, it opens downwards.
In our case, \(a\) is \(-0.01\), which means the parabola will open downwards.
This function can be written in the general form \(ax^2 + bx + c\), where:\
- \(a\), \(b\), and \(c\) are constants
- \(a\) is not equal to zero
If \(a\) is positive, the parabola opens upwards, and if \(a\) is negative, it opens downwards.
In our case, \(a\) is \(-0.01\), which means the parabola will open downwards.
Power Rule
The power rule is one of the foundational rules in calculus for finding derivatives. It states that if you have a term \(ax^n\), its derivative is \(n \times ax^{n-1}\).
Let's break this down with the given function \(f(x)=-0.01x^2 + 0.4x + 50\).
Let's break this down with the given function \(f(x)=-0.01x^2 + 0.4x + 50\).
- For the term \(-0.01x^2\), apply the power rule: multiply the exponent by the coefficient and reduce the exponent by 1:
- For the term \(0.4x\), the exponent of \(x\) is 1. Using the power rule, the result is simply the coefficient \(0.4\).
- The constant term \(50\) has a power of 0, and its derivative is always 0.
Derivative Calculations
Derivative calculations help us understand the rate at which a function changes. For example, in the function \(f(x)=-0.01x^2 + 0.4x + 50\), calculating the derivative provides a new function that tells us the slope of the original function at any point.
\(-0.01x^2\): The power rule gives us \(-0.01 \times 2 \times x^{2-1} = -0.02x\)
\(0.4x\): The power rule gives us \(0.4 \times 1 \times x^{1-1} = 0.4\)
The constant term \(50\) drops out because its derivative is 0.
Now, combine these individual derivatives to get the final result:
\(f^{\rightarrow}(x) = -0.02x + 0.4\)
This new function \(-0.02x + 0.4\) represents the rate of change of the original function \(f(x)\).
- First, identify each term separately: \(-0.01x^2\), \(0.4x\), and \(50\).
- Apply the power rule to each term:
\(-0.01x^2\): The power rule gives us \(-0.01 \times 2 \times x^{2-1} = -0.02x\)
\(0.4x\): The power rule gives us \(0.4 \times 1 \times x^{1-1} = 0.4\)
The constant term \(50\) drops out because its derivative is 0.
Now, combine these individual derivatives to get the final result:
\(f^{\rightarrow}(x) = -0.02x + 0.4\)
This new function \(-0.02x + 0.4\) represents the rate of change of the original function \(f(x)\).