Problem

Integrate Using u-Substitution integral of 1/(y square root of y) with respect to y

The problem is an integral calculus question where you are asked to evaluate the integral of a given function, 1/(y * √y), with respect to the variable y using the u-substitution method. U-substitution is a technique used to simplify integrals by substituting a part of the integrand with a new variable, u, which often converts the integral into a simpler form that is easier to evaluate. In this particular problem, you would typically look for a function within the integrand whose derivative is also present, or simplify the integrand to make the substitution apparent, and then proceed with the integration after substituting the identified part with u.

$\int \frac{1}{y \sqrt{y}} d y$

Answer

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Solution:

Step 1:

We cannot use u-substitution to solve this integral. An alternative approach will be used.

Step 2:

Begin by simplifying the integrand.

Step 2.1:

Start simplification.

Step 2.1.1:

Convert the square root to an exponent using the rule $\sqrt[n]{a^{x}} = a^{\frac{x}{n}}$. Thus, $\sqrt{y}$ becomes $y^{\frac{1}{2}}$. The integral now is $\int \frac{1}{y \cdot y^{\frac{1}{2}}} dy$.

Step 2.1.2:

Combine the terms $y$ and $y^{\frac{1}{2}}$ by summing their exponents.

Step 2.1.2.1:

Combine $y$ and $y^{\frac{1}{2}}$.

Step 2.1.2.1.1:

Express $y$ as $y^1$. The integral becomes $\int \frac{1}{y^{1} y^{\frac{1}{2}}} dy$.

Step 2.1.2.1.2:

Apply the exponent rule $a^{m} a^{n} = a^{m + n}$ to combine the exponents. The integral simplifies to $\int \frac{1}{y^{1 + \frac{1}{2}}} dy$.

Step 2.1.2.2:

Express the number 1 as a fraction with a common denominator. The integral is now $\int \frac{1}{y^{\frac{2}{2} + \frac{1}{2}}} dy$.

Step 2.1.2.3:

Combine the numerators over the common denominator. The integral is $\int \frac{1}{y^{\frac{2 + 1}{2}}} dy$.

Step 2.1.2.4:

Add the numbers 2 and 1. The integral becomes $\int \frac{1}{y^{\frac{3}{2}}} dy$.

Step 2.2:

Now apply the basic rules of exponents.

Step 2.2.1:

Rewrite $y^{\frac{3}{2}}$ as a negative exponent by raising it to the power of $-1$. The integral is $\int (y^{\frac{3}{2}})^{-1} dy$.

Step 2.2.2:

Multiply the exponents in $(y^{\frac{3}{2}})^{-1}$.

Step 2.2.2.1:

Use the power rule for exponents, $(a^{m})^{n} = a^{mn}$. The integral becomes $\int y^{\frac{3}{2} \cdot -1} dy$.

Step 2.2.2.2:

Perform the multiplication of $\frac{3}{2} \cdot -1$.

Step 2.2.2.2.1:

Combine $\frac{3}{2}$ and $-1$. The integral is now $\int y^{\frac{3 \cdot -1}{2}} dy$.

Step 2.2.2.2.2:

Multiply 3 by $-1$. The integral simplifies to $\int y^{\frac{-3}{2}} dy$.

Step 2.2.2.3:

Bring the negative sign in front of the fraction. The integral is $\int y^{-\frac{3}{2}} dy$.

Step 3:

According to the Power Rule for integration, the integral of $y^{-\frac{3}{2}}$ with respect to $y$ is $-2y^{-\frac{1}{2}} + C$.

Step 4:

Finally, simplify the result.

Step 4.1:

Rewrite $-2y^{-\frac{1}{2}} + C$ as $-2\frac{1}{y^{\frac{1}{2}}} + C$.

Step 4.2:

Proceed with simplification.

Step 4.2.1:

Combine $-2$ and $\frac{1}{y^{\frac{1}{2}}}$. The result is $\frac{-2}{y^{\frac{1}{2}}} + C$.

Step 4.2.2:

Place the negative sign in front of the fraction to get the final answer: $-\frac{2}{y^{\frac{1}{2}}} + C$.

Knowledge Notes:

  1. u-Substitution: A technique used in integration, which involves substituting a part of the integrand with a new variable 'u' to simplify the integral. It's not applicable in this case.

  2. Simplifying the Integrand: Before integrating, it can be helpful to simplify the expression by rewriting square roots as exponents and combining like terms.

  3. Exponent Rules: Important rules include $\sqrt[n]{a^{x}} = a^{\frac{x}{n}}$, $a^{m} a^{n} = a^{m + n}$, and $(a^{m})^{n} = a^{mn}$. These rules are used to simplify the integrand before integrating.

  4. Power Rule for Integration: For any real number $n \neq -1$, the integral of $x^n$ with respect to $x$ is $\frac{x^{n+1}}{n+1} + C$, where C is the constant of integration. This rule is used to find the antiderivative of the given function.

  5. Negative Exponents: A term with a negative exponent, such as $x^{-n}$, can be rewritten as $\frac{1}{x^n}$. This is used to move terms from the denominator to the numerator or vice versa when simplifying expressions.

  6. Constants of Integration: When performing indefinite integration, a constant of integration (denoted as 'C') is added to the result to account for all possible antiderivatives.

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