1.92: Estimate roots using a graph

The grid opposite shows the graph of $y=3x\sin x$ for $-1\le x\le3$, where $x$ is measured in radians.

(a) Use the graph to estimate, to 1 decimal place, the roots of the equation $x\sin x=1$ in the interval $-1\le x\le3$. (3)

(b) By drawing a suitable straight line on the grid, obtain estimates, to 1 decimal place, of the roots of the equation $2x\sin x-x=1$ in the interval $-1\le x\le3$. (5)