Graph of y = cos x on a grid. The x-axis ranges from 0 to 15, and the y-axis ranges from -1 to 1. The graph shows a cosine wave with amplitude 1 and period 2π. Key points include (0, 1), (π/2, 0), (π, -1), (3π/2, 0), and (2π, 1). The label 'y = cos x' is in the top right corner.
Use the graph of y=cosx to solve, correct to 1 decimal place: