Signs of the trigonometric functions in the first quadrant

Name

Signs of the trigonometric functions in the first quadrant
$\text{P is any point in the first quadrant}\,$

$\overline {ON}\text{ x-coordinate or abscissa of point P, positive}\,$

$\overline {OM}\text{ y-coordinate or ordinate of point P, positive}\,$

$\overline {OP}\text{ distance from the origin, always}\,$

$\text{positive because it is a length}\,$

$\overline {OM}=\overline{NP}\,$

$\sin \alpha=\frac{\overline{NP}}{\overline {OP}}=\frac{\text{y-coordinate}}{\text{distance from the origin}}=\frac{a}{b}\qquad \color{Red}+$
$\cos \alpha=\frac{\overline{ON}}{\overline {OP}}=\frac{\text{x-coordinate}}{\text{distance from the origin}}=\frac{c}{b}\qquad \color{Red}+$
$\tan \alpha=\frac{\overline{NP}}{\overline {ON}}=\frac{\text{y-coordinate}}{\text{x-coordinate}}=\frac{a}{c}\qquad \color{Red}+$
$\cot \alpha=\frac{\overline{ON}}{\overline {NP}}=\frac{\text{x-coordinate}}{\text{y-coordinate}}=\frac{c}{a}\qquad \color{Red}+$
$\sec \alpha=\frac{\overline{OP}}{\overline {ON}}=\frac{\text{distance from the origin}}{\text{x-coordinate}}=\frac{b}{c}\qquad \color{Red}+$
$\csc \alpha=\frac{\overline{OP}}{\overline {NP}}=\frac{\text{distance from the origin}}{\text{y-coordinate}}=\frac{b}{a}\qquad \color{Red}+$

Usage

• Write here usage for the table