# Maths - CAST

> Source: https://ollybritton.com/notes/a-level/maths/topics/cast/ · Updated: 2024-08-24 · Tags: maths

##### What does CAST stand for??
* Cosine
* All
* Sine
* Tan

##### What does CAST tell you??
When the values of trig functions are positive or negative.

##### What should CAST actually be called??
ASTC

##### What region of CAST are acute angles in??
A/All.

##### What region of CAST are obtuse angles in??
S/Sin.

##### What region of CAST are small reflex angles in??
T/Tan.

##### What region of CAST are large reflex angles in??
C/Cos.

##### What is the inequality for an acute angle??
$$
0^{\circ} < x < 90^{\circ}
$$

##### What is the inequality for an obtuse angle??
$$
90^{\circ} < x < 180^{\circ}
$$

##### What is the inequality for a small reflex angle??
$$
180^{\circ} < x < 270^{\circ}
$$

##### What is the inequality for a large reflex angle??
$$
270^{\circ} < x < 360^{\circ}
$$

##### Visualise a CAST diagram??
![PHOTO CAST](paste-9df747673e3470e2510a2210d823073a4058b6e1.jpg)

##### What trig functions are positive for acute angles??
All of them.

##### What trig functions are positive for obtuse angles??
$$
\sin
$$

##### What trig functions are positive for small reflex angles??
$$
\tan
$$

##### What trig functions are positive for large reflex angles??
$$
\cos
$$

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