Basic Mathematics and Measurements
2.0 Trigonometry
2.1 Values of trigonometric angles
2.2 Trigonometric identities
2.3 Trigonometric functions in different quadrants
2.0 Trigonometry
2.2 Trigonometric identities
2.3 Trigonometric functions in different quadrants
Basics of trigonometry start by understanding a right-angled triangle.
where,
$p:$ Perpendicular
$b:$ Base
$h:$ Hypotenuse
We can write various trigonometric functions as,
| S. No. | Trigonometric function | Formula |
| 1. | Sine | $$\sin \theta = \frac{p}{h}$$ |
| 2. | Cosine | $$\cos \theta = \frac{b}{h}$$ |
| 3. | Tangent | $$\tan \theta = \frac{p}{b}$$ |
| 4. | Cotangent | $$\cot \theta = \frac{b}{p}$$ |
| 5. | Secant | $$\sec \theta = \frac{h}{b}$$ |
| 6. | Cosecant | $$\cos ec\theta = \frac{h}{p}$$ |
Relation between different trigonometric functions are,
(A) Sine and cosecant $$\sin \theta = \frac{1}{{\cos ec\theta }}$$
(B) Cosine and secant $$\cos \theta = \frac{1}{{\sec \theta }}$$
(C) Tangent and cotangent $$\tan \theta = \frac{1}{{\cot \theta }}$$
Relation between degree and radian
$$\left[ {{\text{Radian}}} \right] = \frac{\pi }{{180^\circ }} \times \left[ {{\text{Degree}}} \right]$$
Example: Convert ${30^\circ }$ into radians.
$$\left[ {{\text{Radian}}} \right] = \frac{\pi }{{180^\circ }} \times 30^\circ $$$$\left[ {{\text{Radian}}} \right] = \frac{\pi }{6}$$
