Chapter 4: Problem 15
If \(b=-1 / 2\), evaluate \(-b^{3}\).
Short Answer
Expert verified
The value of \(-b^3\) when \(b = -1/2\) is \(1/8\).
Step by step solution
01
Identify the Expression
The expression we need to evaluate is \[-b^3.\]
02
Substitute the Value of b
Plug in the value of \(b=-1/2\) into the expression. This gives us:\[-(-1/2)^3.\]
03
Calculate the Cube of b
Calculate \((-1/2)^3\). Using the property of exponents, this is:\[(-1)^3 = -1\quad \text{and} \quad (2)^3 = 8,\]which results in:\[(-1)^3 / (2)^3 = -1/8.\]
04
Simplify Negation
Now simplify the negative sign in front of the expression:\[-(-1/8) = 1/8.\]
05
Verify the Calculation
Go through the steps to ensure correctness: substituting \(b = -1/2\), cubing it gives \(-1/8\), and negating it results in \(1/8\). Everything checks out.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Exponents
In mathematics, exponents are a way to express repeated multiplication of a number. If we have a number "a" raised to the power "n," written as \(a^n\), it means that "a" is multiplied by itself "n" times. Let's imagine you have a small warehouse with boxes arranged neatly. If you place them in a line, one after another, that's similar to multiplying a number. But when you pile them up as in, say, a cube, you're entering the realm of exponents.
Here are some points to remember about exponents:
As you work with exponents, you'll also encounter rules like the "power of a power" where \((a^m)^n = a^{m \times n}\). In our exercise, we dealt with squaring \((-1/2)\), which means multiplying \((-1/2)\) by itself three times, representing a real-world scenario of working with layers or iterations.
Here are some points to remember about exponents:
- An exponent of 1 (like \(a^1\)) means the number remains itself.
- The zero exponent (like \(a^0\)) is a special case that always equals 1, as long as "a" is not zero.
- Negative exponents indicate division or a "flipping" of the base, changing \(a^{-n}\) to \(1/a^n\).
As you work with exponents, you'll also encounter rules like the "power of a power" where \((a^m)^n = a^{m \times n}\). In our exercise, we dealt with squaring \((-1/2)\), which means multiplying \((-1/2)\) by itself three times, representing a real-world scenario of working with layers or iterations.
Negative numbers
Negative numbers are numbers less than zero. They are often represented with a minus sign (-) in front. These numbers can indicate a loss, a temperature drop, or moving in the opposite direction. In math, they play a crucial role and require careful handling when performing operations.
Some basic points about negative numbers include:
In the given exercise, we dealt with the negative value of "\(b\)", being \(-1/2\). When cubing the negative number \((-1)\), it becomes \(-1\). This neat trick of sign change derives from multiplying a negative number an odd number of times, leaving us with a negative result to consider in calculations. Remember this whenever you handle negative numbers in math.
Some basic points about negative numbers include:
- When you multiply two negative numbers, the result is positive.
- Multiplying a negative with a positive results in a negative number.
- Adding two negative numbers gives an even more negative number.
In the given exercise, we dealt with the negative value of "\(b\)", being \(-1/2\). When cubing the negative number \((-1)\), it becomes \(-1\). This neat trick of sign change derives from multiplying a negative number an odd number of times, leaving us with a negative result to consider in calculations. Remember this whenever you handle negative numbers in math.
Fractions
Fractions are a way to express numbers that are not whole. They come in the form \(\frac{a}{b}\), where "a" is the numerator (top part) and "b" is the denominator (bottom part). Think of a pizza cut into slices. Each slice represents a fraction of the whole pizza.
Key points about fractions include:
In our problem, we had the fraction \(-1/2\). When raised to the power of three, both the numerator and the denominator were cubed separately, resulting in a new fraction \((-1/8)\). To make math involving fractions easier, always remember to break down the problem step by step, ensuring each part is handled with care.
Key points about fractions include:
- Fractions with the same denominator can be easily compared or added.
- Inverting a fraction (flipping the numerator and denominator) gives its reciprocal, needed for division.
- Multiplying fractions is straightforward: multiply the numerators together and the denominators together.
In our problem, we had the fraction \(-1/2\). When raised to the power of three, both the numerator and the denominator were cubed separately, resulting in a new fraction \((-1/8)\). To make math involving fractions easier, always remember to break down the problem step by step, ensuring each part is handled with care.