Verified Answer :

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Answer:

\(\displaystyle \int\limits^{49}_{36} {\frac{ln(y)}{\sqrt{y}}} \, dy = 28ln(7) - 24ln(6) - 4\)

General Formulas and Concepts:

Algebra I

  • Exponential Rule [Rewrite]:                                                                           \(\displaystyle b^{-m} = \frac{1}{b^m}\)
  • Exponential Rule [Root Rewrite]:                                                                 \(\displaystyle \sqrt[n]{x} = x^{\frac{1}{n}}\)

Calculus

Derivatives

Derivative Notation

Basic Power Rule:

  • f(x) = cxⁿ
  • f’(x) = c·nxⁿ⁻¹

Logarithmic Derivative:                                                                                         \(\displaystyle \frac{d}{dx} [lnu] = \frac{u'}{u}\)

Integrals

  • Definite Integrals

Integration Rule [Reverse Power Rule]:                                                               \(\displaystyle \int {x^n} \, dx = \frac{x^{n + 1}}{n + 1} + C\)

Integration Rule [Fundamental Theorem of Calculus 1]:                                     \(\displaystyle \int\limits^b_a {f(x)} \, dx = F(b) - F(a)\)

Integration Property [Multiplied Constant]:                                                         \(\displaystyle \int {cf(x)} \, dx = c \int {f(x)} \, dx\)

Integration by Parts:                                                                                               \(\displaystyle \int {u} \, dv = uv - \int {v} \, du\)

  • [IBP] LIPET: Logs, inverses, Polynomials, Exponentials, Trig

Step-by-step explanation:

Step 1: Define

Identify

\(\displaystyle \int\limits^{49}_{36} {\frac{ln(y)}{\sqrt{y}}} \, dy\)

Step 2: Integrate Pt. 1

Identify and find variables for Integration by Parts.

  1. [LIPET] Set:                                                                                                     \(\displaystyle u = ln(y)\)
  2. [LIPET] Set:                                                                                                     \(\displaystyle dv = \frac{1}{\sqrt{y}} \ dy\)
  3. [u] Differentiate [Logarithmic Derivative]:                                                   \(\displaystyle \frac{du}{dy} = \frac{1}{y}\)
  4. [u] Rewrite:                                                                                                     \(\displaystyle du = \frac{1}{y} \ dy\)
  5. [dv] Integrate [Integration Rule - Reverse Power Rule]:                             \(\displaystyle v = 2\sqrt{y}\)

Step 3: Integrate Pt. 2

  1. [Integral] Integration by Parts:                                                                       \(\displaystyle \int\limits^{49}_{36} {\frac{ln(y)}{\sqrt{y}}} \, dy = \bigg[ 2ln(y)\sqrt{y} \bigg] \bigg| \limits^{49}_{36} - \int\limits^{49}_{36} {\frac{2\sqrt{y}}{y}} \, dy\)
  2. [Integral] Simplify/Rewrite [Integration Property - Multiplied Constant]:   \(\displaystyle \int\limits^{49}_{36} {\frac{ln(y)}{\sqrt{y}}} \, dy = \bigg[ 2ln(y)\sqrt{y} \bigg] \bigg| \limits^{49}_{36} - 2\int\limits^{49}_{36} {\frac{1}{\sqrt{y}}} \, dy\)
  3. [Integral] Reverse Power Rule:                                                                     \(\displaystyle \int\limits^{49}_{36} {\frac{ln(y)}{\sqrt{y}}} \, dy = \bigg[ 2ln(y)\sqrt{y} \bigg] \bigg| \limits^{49}_{36} - 2 \bigg[ 2\sqrt{y} \bigg] \bigg| \limits^{49}_{36}\)
  4. Evaluate [Integration Rule - FTC 1]:                                                             \(\displaystyle \int\limits^{49}_{36} {\frac{ln(y)}{\sqrt{y}}} \, dy = 28ln(7) - 24ln(6) - 2(2)\)
  5. Simplify:                                                                                                         \(\displaystyle \int\limits^{49}_{36} {\frac{ln(y)}{\sqrt{y}}} \, dy = 28ln(7) - 24ln(6) - 4\)

Topic: AP Calculus AB/BC (Calculus I/I + II)

Unit: Integration

Book: College Calculus 10e