Here is a handy reference for the major trigonometric function values for the "famous" angles in the first quadrant and at 0° and 90°, which technically are on the x-axis and y-axis respectively, not in the first quadrant but instead on the borders.
Here are a few well known properties of these functions over this range.
1. Sine and tangent are increasing. While sine increases, it is bounded by 1 as the highest possible value. Tangent is unbounded and can get as large as any positive number you can name. As I said in class, tangent is the same as the slope of the line that connects the origin (0, 0) to the point (cos alpha, sin alpha). (The editor in Blogger is bound by the symbols available in HTML, so I will have to spell out Greek letters when used as variables.)
2. Cosine is decreasing over the range.
3. Cosine is short for "complementary sine", which means cos(90°-alpha)= sin alpha, when alpha is an angle measured in degrees. In the other direction, sin(90°-alpha)= cos alpha.
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