Question

how to define trigonometry ratioes​

Answer 1

Trigonometric Ratios. The six trigonometric ratios relate the sides of a right triangle to its angles. Specifically, they are ratios of two sides of a right triangle and a related angle. Trigonometric functions are typically used to calculate unknown lengths or angles in a right triangle.

Answer 2

Consider a right angled triangle, with one of its angle as 90°.

1) sin theta = perpendicular/hypotenuse.

2) cos theta = base/hypotenuse.

3) tan theta = perpendicular/base.

Just remember this three.

Feeling uneasy to remember? Go with a simple trick.

1] Some People Have (sin theta = Perpendicular/Hypotenuse)

2] Curly Brown Hair (cos theta = base/hypotenuse)

3] Turned Permanently Black (tan theta = perpendicular/base)

Now, cosec theta, sec theta and cot theta are just the reverse (or reciprocal) of the above three mentioned ratios.

4] cosec theta = 1/sin theta = hypotenuse/perpendicular.

5] sec theta = 1/cos theta = hypotenuse/base.

6] cot theta = 1/tan theta = base/perpendicular

Now, feeling easy? I am sure that you are.

By using that poem, remember the first three trigonometric ratios.

For the next three, no need of giving stress to your brain since they are thereciprocals of the above three respectively.