Key Takeaways A sine wave is an S-shaped waveform defined by the mathematical function y = sin x. It is depicted graphically as two semi-circular curves that alternate above and below a center line.

x = 30 ∘ Draw the horizontal line y = 0.5. The line y = 0.5 crosses the graph of y = sin x four times in the interval 360 ∘ ≤ θ ≤ 360 ∘ so there are four solutions.

Applications of acosx + bsinx Given any expression of the form a cos x + b sin x it is better to rewrite it into one of the forms k cos (x ± α) or k sin (x ± α) before answering the question.