Chapter 6: Problem 2
Expand \((1+i)^{2}=?\)
Short Answer
Expert verified
The expansion of \((1+i)^{2}\) is \(2i\).
Step by step solution
01
Binomial Theorem
Use the Binomial Theorem, which states that \( (a+b)^{2} = a^{2} + 2ab + b^{2} \). Hence, for \( (1+i)^{2} \), \( a = 1 \) and \( b = i \).
02
Substituting into the formula
Substitute \( a \) and \( b \) into the formula to get the expanded form, thus it will become \( 1^{2} + 2*1*i + i^{2} \).
03
Simplification
Simplify each term separately. \( 1^{2} = 1 \), \( 2*1*i = 2i \), and most importantly, remember that \( i^{2} = -1 \). Thus, the expression becomes \( 1 + 2i -1 \).
04
Final Answer
Combine like terms to get the final answer. The \( 1 \) and \( -1 \) cancel out, so the answer is \( 2i \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Binomial Theorem
The binomial theorem is a fundamental principle in algebra. It provides a formula to expand expressions that are raised to a power. In simple terms, it helps you break down expressions like \((a+b)^n\) into a manageable sum of terms. For our specific example \((1+i)^2\),
Understanding the binomial theorem is a great starting point in mastering algebra. It holds significance in many mathematical areas and solutions.
- The binomial theorem tells us that \((a+b)^2 = a^2 + 2ab + b^2\).
- By comparing, you can see that both "a" and "b" are parts of our starting expression, \((1+i)\).
- Here, \(a = 1\) and \(b = i\).
Understanding the binomial theorem is a great starting point in mastering algebra. It holds significance in many mathematical areas and solutions.
Imaginary Unit
The imaginary unit, denoted as \(i\), is a concept from complex numbers used to represent the square root of a negative number. Specifically, \(i\) represents \(\sqrt{-1}\). A major feature of \(i\) is the interesting property that \(i^2 = -1\). This property is crucial in our exercise:
- When expanding \((1+i)^2\), \(i^2\) becomes \(-1\), which changes our result significantly.
- This transformation from \(i^2\) to \(-1\) is an essential step that simplifies complex number calculations.
Algebraic Expansion
Algebraic expansion transforms expressions into longer ones by removing brackets and combining like terms. In our case of \((1+i)^2\), algebraic expansion plays a key role. Here’s a breakdown of the process that occurs with our example:
- The original expression \((1+i)^2\) is expanded using the binomial theorem. Substituting gives \(1^2 + 2 \cdot 1 \cdot i + i^2\).
- Each term is calculated separately: \(1^2 = 1\), \(2 \cdot 1 \cdot i = 2i\), and \(i^2 = -1\).
- Combining these results, you simplify to \(1 + 2i - 1 = 2i\).