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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 7.3.101

Evaluate the integrals in Exercises 97–110.
101. ∫ (log₁₀x / x) dx

Guida verificata passo dopo passo
1
Recognize that the integral is \( \int \frac{\log_{10} x}{x} \, dx \). Since the logarithm is base 10, recall the change of base formula: \( \log_{10} x = \frac{\ln x}{\ln 10} \), where \( \ln x \) is the natural logarithm.
Rewrite the integral using the natural logarithm: \( \int \frac{\log_{10} x}{x} \, dx = \int \frac{\frac{\ln x}{\ln 10}}{x} \, dx = \frac{1}{\ln 10} \int \frac{\ln x}{x} \, dx \).
Focus on the integral \( \int \frac{\ln x}{x} \, dx \). To solve this, use substitution: let \( t = \ln x \), which implies \( dt = \frac{1}{x} dx \).
Rewrite the integral in terms of \( t \): \( \int t \, dt \), since \( \frac{\ln x}{x} dx = t \, dt \).
Integrate \( \int t \, dt \) to get \( \frac{t^2}{2} + C \), then substitute back \( t = \ln x \) to express the answer in terms of \( x \). Finally, multiply by the constant \( \frac{1}{\ln 10} \) from step 2.

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