Show that(adsbygoogle = window.adsbygoogle || []).push({});

[tex] \lim_{n \rightarrow \infty} \int_{0}^{\pi} Ln(x) Sin(nx) dx [/tex]

i was told to use this identity

given that [itex] int f^2 \rho dx [/itex] is finite then

[tex] c_{n}^2 \int_{a}^{b} \phi_{n}^2 \rho dx = \frac{(\int_{a}^{b} f \phi_{n} \rho dx)^2}{\int_{a}^{b} \phi_{n}^2 \rho dx} \rightarrow 0 [/tex] and n approaches infinity

here Cn are the Fourier Coefficients

but how do i relate this to the problem i have

would rho = log x and phi^2 = sin nx?

Please help!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Fourier Series Proof

**Physics Forums | Science Articles, Homework Help, Discussion**