A wave has the form $y=A \cos (2 \pi x / \lambda+\pi / 3)$ when $x<0$. For $x>0,$ the wavelength is $\lambda / 2 .$ By applying continuity conditions at $x=0,$ find the amplitude (in terms of $A$ ) and phase of the wave in the region $x>0 .$ Sketch the wave, showing both $x<0$ and $x>0$