Reading the solutions off the graph

The solutions of an elementary trigonometric equation such as $\sin x = \tfrac{1}{2}$ are visualised as intersections of the graph with a horizontal line.

The equation $\sin x = 1/2$ on $[0,2\pi)$ has two solutions, $\pi/6$ and $5\pi/6$, corresponding to the two intersections of the graph of $\sin$ with the horizontal line $y=1/2$.

Adding $2k\pi$ to each of the two solutions gives all the infinitely many solutions of the equation.

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Topics: Trigonometry
Concepts: Trigonometric equation · Sine
Functions: Sine
Skills: Interpreting graphs · Solving equations