Chapter 1: Problem 84
Rationalize the denominator. $$\frac{1}{\sqrt{x}+1}$$
Short Answer
Expert verified
\( \frac{\sqrt{x}-1}{x-1} \) is the rationalized form.
Step by step solution
01
Identify the Problem
We need to rationalize the denominator of the expression \( \frac{1}{\sqrt{x}+1} \). This involves removing the square root from the denominator.
02
Multiply by the Conjugate
To rationalize \( \frac{1}{\sqrt{x}+1} \), multiply both the numerator and the denominator by the conjugate of the denominator, which is \( \sqrt{x}-1 \). This gives us:\[\frac{1}{\sqrt{x}+1} \times \frac{\sqrt{x}-1}{\sqrt{x}-1} = \frac{\sqrt{x}-1}{(\sqrt{x}+1)(\sqrt{x}-1)}.\]
03
Simplify the Denominator
Use the difference of squares formula \((a+b)(a-b) = a^2-b^2\) to simplify the denominator:\[(\sqrt{x}+1)(\sqrt{x}-1) = (\sqrt{x})^2 - 1^2 = x - 1.\]
04
Simplify the Fraction
Now the expression becomes:\[\frac{\sqrt{x}-1}{x-1}.\]The denominator is now rationalized since it does not contain a square root.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Square Root
A square root is a value that, when multiplied by itself, gives the original number. The square root of a number \( x \) is written as \( \sqrt{x} \). For positive values, this represents the principal square root. For instance, the square root of 9 is 3 because \( 3 \times 3 = 9 \).
- Square roots are the inverse operation of squaring numbers.
- They are useful in solving quadratic equations and simplifying radical expressions.
Difference of Squares
The difference of squares is a mathematical identity used to simplify expressions with two terms squared and subtracted. It states that:\[ (a+b)(a-b) = a^2 - b^2, \]where \( a \) and \( b \) are any expressions. This identity is instrumental in rationalizing denominators that contain square roots.
- This technique is effective because it eliminates the middle term, \( ab - ba \).
- It transforms expressions into simpler forms with integer coefficients.
Conjugate in Algebra
In algebra, the conjugate of a binomial expression like \( a + b \) is \( a - b \), and vice versa. Using conjugates is a strategic method employed to rationalize denominators containing radicals or complex numbers.
- Conjugates rely on the difference of squares identity to clear out radicals.
- They are essential for rewriting expressions in a simpler form.