- 1). Focus one complete period of a trigonometric function. One period for cosine lies within the interval (0, PI); a period for sine lies within the interval (-PI / 2, PI / 2); a period for tangent lies within the interval (-PI / 2, PI / 2); a period for secant lies within the interval (0, PI).
- 2). Reflect the graph of a trigonometric function about the line y = x. This is a diagonal line with slope = 1 with an x- and y-intercept at 0. To do this, choose several points from the original function and reverse the coordinates. For instance, if the original trig function has an x-value at (PI, -1), the inverse trig function will have a point at (-1, PI).
- 3). Plot several reflected points onto the graph in order to have enough points to draw an accurate curve. Use at least one point per each one unit interval. For instance, for cosine an appropriate number of plot points would include: x = 0, x = 1, x = 2, x = PI.
- 4). Connect the plotted points with a smooth curve to complete the graph of the inverse function. The result is a mirror image of the original trigonometric function about the line y = x.
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