If tan θ = \( \frac{b}{a} \), then \(\frac{a\cos\theta+b\sin\theta}{a\cos\theta-b\sin\theta}\) = ______
\(\frac{a^2-b^2}{a^2+b^2}\)
\(\frac{a-b}{a+b}\)
\(\frac{a^2+b^2}{a^2-b^2}\)
\(\frac{a+b}{a-b}\)
C. \(\frac{a^2+b^2}{a^2-b^2}\)
