manque indice

$$V_{out,2} = \frac{V_{in,2}}{\sqrt{1 + R_{2}^2\omega^2C_{2}^2}}
\left(\frac{e^{\frac{-t}{R_{2}C_{2}}}}{\sqrt{1 + R_{2}^2\omega^2C_{2}^2}} - 
\cos(\arctan(-R_{2}C_{2}\omega) + \omega t)\right) + """""""V_{in,2}\cos(\omega t)$$"""""""