## Right-angled triangle definitions

In the formulas below $\text{hypotenuse }$denotes the length of the longest side of a right-angled triangle, the side opposite the right angle. For a non-right angle $\alpha$, $\text{opposite}$ denotes the length of the side across $\alpha$ whereas $\text{adjacent}$ is the length of the short side that is next to $\alpha$.

• Sine

$\sin\alpha=\text{opposite}\div\text{hypotenuse}$

• Cosine

$\cos\alpha=\text{adjacent}\div\text{hypotenuse}$

• Tangent

$\tan\alpha=\text{opposite}\div\text{adjacent}$

• Cosecant

$\csc\alpha=\text{hypotenuse}\div\text{opposite}$

• Secant

$\sec\alpha=\text{hypotenuse}\div\text{adjacent}$

• Cotangent

$\cot\alpha=\text{adjacent}\div\text{opposite}$

To evaluate the inverse of a function, turning a function value into an angle, feed the value into the “Function Value” control.

## Angle units

To express angles, you may use one of the following units:

• Radians - with complete turn $\alpha=2\pi$
• Degrees - with complete turn $\alpha=360°$
• Minute of arc - with complete turn $\alpha=21,600'$
• Second of arc - with complete turn $\alpha=1,296,000''$
• Grad - with complete turn $\alpha=400$
• Turns/Revisions - with complete turn $\alpha=1\text{ rev}$