on comparing with standard equation of stationary wave
\(y=R \sin \frac{2 \pi \mathrm{x}}{\lambda} \cdot \sin \omega \mathrm{t},\) we get
\(\frac{2 \pi \mathrm{x}}{\lambda}=\mathrm{bx}\)
\(\lambda=\frac{2 \pi}{b}\)
The distance between constructive nodes
\(=\frac{\lambda}{2}=\frac{2 \pi / \mathrm{b}}{2}=\frac{\pi}{\mathrm{b}}\)