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Ch. 7 - Transcendental Functions
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Non è quello che usi tu?Cambia libro di testo
Capitolo 7, Problema 7.2.73

73. Find the area between the curves y=ln(x) and y=ln(2x) from x=1 to x=5.

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Identify the two functions given: \( y = \ln(x) \) and \( y = \ln(2x) \). We want to find the area between these curves from \( x = 1 \) to \( x = 5 \).
Determine which function is on top and which is on the bottom in the interval \( [1, 5] \). Since \( \ln(2x) = \ln(2) + \ln(x) \), it is always greater than \( \ln(x) \) for \( x > 0 \). So, \( y = \ln(2x) \) is the upper curve and \( y = \ln(x) \) is the lower curve.
Set up the integral for the area between the curves as \( \int_1^5 [\ln(2x) - \ln(x)] \, dx \).
Simplify the integrand using logarithm properties: \( \ln(2x) - \ln(x) = \ln\left(\frac{2x}{x}\right) = \ln(2) \). So the integral becomes \( \int_1^5 \ln(2) \, dx \).
Evaluate the integral by integrating the constant \( \ln(2) \) over \( [1, 5] \), which is \( \ln(2) \times (5 - 1) \). This gives the area between the curves.

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