Mastering the Mystery of Square Roots and Inequalities: A Comprehensive Guide to Domain, Interval, and Set-Builder Notation


Finding the Domain of √(-5x + 11)

Here are the detailed steps to find the domain of the function √(-5x + 11).

Step 1: Identify the Expression Under the Square Root

The expression under the square root is -5x + 11.

Step 2: Set the Expression to be Non-Negative

For the square root to be real, the expression under it must be non-negative. This leads to the inequality -5x + 11 ≥ 0.

Step 3: Isolate x

To find the values of x that satisfy this inequality, we isolate x on one side.

  • First, move all terms involving x to one side and constants to the other: -5x ≥ -11.
  • Next, divide both sides by -5, remembering to flip the inequality sign: x ≤ 11/5.
  • Finally, simplify the fraction: x ≤ 2.2.

Conclusion

The domain of the function √(-5x + 11) is x ≤ 2.2.

Converting Inequality to Interval Notation: Symbol by Symbol

This section explains how to convert the inequality x ≤ 2.2 into interval notation, focusing on each symbol.

Step 1: Understand the ‘≤’ Symbol

The symbol ‘≤’ is a combination of ‘<' (less than) and '=' (equal to). It means 'less than or equal to'.

Step 2: Break Down the Symbol

We can break down ‘≤’ into two parts: ‘less than’ represented by ‘<' and 'equal to' represented by '='.

Step 3: Convert ‘<' to Interval Notation

In interval notation, ‘less than’ is represented by using a round parenthesis ‘)’. If the inequality was x < 2.2, the interval would be (-∞, 2.2).

Step 4: Convert ‘=’ to Interval Notation

In interval notation, ‘equal to’ is represented by using a square bracket ‘]’. If the inequality was x = 2.2, the interval would be [2.2, 2.2].

Step 5: Combine Both Symbols

Since the original inequality is ‘less than or equal to’, we combine both symbols in interval notation. The interval becomes (-∞, 2.2] which includes both ‘less than’ and ‘equal to’.

Conclusion

The inequality x ≤ 2.2 is represented in interval notation as (-∞, 2.2].

Converting Inequality to Set-Builder Notation: Symbol by Symbol

This section explains how to convert the inequality x ≤ 2.2 into set-builder notation, focusing on each symbol.

Step 1: Understand the ‘≤’ Symbol

The symbol ‘≤’ is a combination of ‘<' (less than) and '=' (equal to). It means 'less than or equal to'.

Step 2: Break Down the Symbol

We can break down ‘≤’ into two parts: ‘less than’ represented by ‘<' and 'equal to' represented by '='.

Step 3: Convert ‘<' to Set-Builder Notation

In set-builder notation, ‘less than’ would be expressed as {x | x < 2.2}.

Step 4: Convert ‘=’ to Set-Builder Notation

In set-builder notation, ‘equal to’ would be expressed as {x | x = 2.2}.

Step 5: Combine Both Symbols

Since the original inequality is ‘less than or equal to’, we combine both symbols in set-builder notation. The set becomes {x | x ≤ 2.2}.

Conclusion

The inequality x ≤ 2.2 is represented in set-builder notation as {x | x ≤ 2.2}.


Unlocking the Calculus Behind \( \sqrt{-5x + 11} \): A Step-by-Step Guide to Finding Its Derivative

Step 1: Rewrite the Function in Exponential Form

We start by rewriting \( \sqrt{-5x + 11} \) in exponential form to make it easier to differentiate. The square root of a number is the same as raising that number to the power of \( \frac{1}{2} \).

\[ \sqrt{-5x + 11} = (-5x + 11)^{\frac{1}{2}} \]

Step 2: Understand the Chain Rule

The chain rule is a fundamental principle in calculus used for differentiating composite functions. It states that the derivative of \( f(g(x)) \) is \( f'(g(x)) \times g'(x) \).

\[ (f(g(x)))’ = f'(g(x)) \times g'(x) \]

Step 3: Identify the Outer and Inner Functions

In our function \( (-5x + 11)^{\frac{1}{2}} \), the outer function is \( f(u) = u^{\frac{1}{2}} \) and the inner function is \( g(x) = -5x + 11 \).

Step 4: Differentiate the Outer Function

We first find the derivative of the outer function \( f(u) = u^{\frac{1}{2}} \) with respect to \( u \).

\[ f'(u) = \frac{1}{2} u^{-\frac{1}{2}} \]

Step 5: Differentiate the Inner Function

Next, we find the derivative of the inner function \( g(x) = -5x + 11 \) with respect to \( x \).

\[ g'(x) = -5 \]

Step 6: Apply the Chain Rule

Now we apply the chain rule by multiplying the derivative of the outer function evaluated at the inner function by the derivative of the inner function.

\[ \frac{d}{dx} \left( (-5x + 11)^{\frac{1}{2}} \right) = \frac{1}{2} (-5x + 11)^{-\frac{1}{2}} \times (-5) \]

Step 7: Simplify the Expression

Finally, we simplify the expression to get the derivative of the original function.

\[ \frac{-5}{2} (-5x + 11)^{-\frac{1}{2}} = -\frac{5}{2\sqrt{-5x + 11}} \]

Conclusion

The derivative of \( \sqrt{-5x + 11} \) is \( -\frac{5}{2\sqrt{-5x + 11}} \).

Why the Derivative of \( \sqrt{-5x + 11} \) Is Not Defined at \( x = 2.2 \): A Detailed Explanation

Step 1: Recall the Original Function

The original function is \( \sqrt{-5x + 11} \), which we rewrote as \( (-5x + 11)^{\frac{1}{2}} \) for differentiation.

Step 2: Examine the Derivative

The derivative we found is \( -\frac{5}{2\sqrt{-5x + 11}} \).

Step 3: Identify the Denominator

The derivative has a denominator of \( 2\sqrt{-5x + 11} \). For the derivative to be defined, this denominator cannot be zero.

Step 4: Set the Denominator Equal to Zero

Setting \( 2\sqrt{-5x + 11} = 0 \) and solving, we find that the denominator is zero when \( x = 2.2 \).

Step 5: Understand the Implication

Because the denominator of the derivative is zero at \( x = 2.2 \), the derivative is undefined at this point.

Conclusion

The derivative of \( \sqrt{-5x + 11} \) is not defined at \( x = 2.2 \) because the denominator of the derivative becomes zero, making the expression undefined.