Jeremy uses the
Using a unit circle:
Draw a Unit circle and estimate
Circle, with horizontal diameter, & radius to point in the first quadrant on the circle, with central angle labeled, 37 degrees.
Since sin is height, draw in the height to the
Added to diagram, vertical segment from point in first quadrant on circle, perpendicular to x axis.
Find and draw the same height any other place it may occur on the unit circle.
Added to diagram, additional vertical segment, of same height, reflected over the, y axis, in the second quadrant.
Calculate the new angles.
Added to diagram, segment from point in second quadrant on circle to center, with angle from positive x axis, to the new segment, labeled 143 degrees.
Using a graph:
Draw the sine curve.
Repeating wave curve, first visible low & high points: (negative pi halves, comma negative 1) & (pi halves, comma 1), continuing in that pattern, just past 4 pi.
Added to graph, horizontal line at approximately, y = 0.6.
Added to graph, red points at the intersections of the horizontal line with the wave curve, left of negative pi, pi, & 3 pi. Blue points at the intersections, right of, y axis, 2 pi, & 4 pi.
Label the solution
Label added to first blue point, right of, y axis, 37 degrees.
Use Symmetry to find other solutions.
Labels added to red points, from left to right, 143 degrees minus 2 pi, 143 degrees, 143 degrees + 2 pi. Labels added to other blue points, from left to right, 37 degrees + 2 pi, 37 degrees + 4 pi.