## Sec, Cosec, Cot

Sec, cosec and cot are all functions in trigonometry. They are simply equal to one over on of the other functions, ie cos, sin and tan.

so

Sec = 1/cos

Cosec = 1/sin

cot = 1/tan

You can remember which is paired with which using the third letter rule. This is that the third letter is the first letter of the corresponding function ie)

se**c **goes with **c**os

co**s**ec goes with **s**in

co**t** goes with **t**an

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Categories: maths
cos, cosec, cot, sec, sin, tan, third letter rule, Trigonometry

If Tan=sin/cos, then whats Sin=?, and Cos?

Tan, sin and cos are to do with the ratios of the sides of right angled triangles with a given angle in one of the corners.

Tan = sin/cos can derived from these ratios, or these ratios can be derived from defining tan as sin/cos.

In answer to your question,

sin = opposite/hypotenuse

cos = adjacent over hypotenuse

where the hypotenuse is the longest side of the right angled triangle, the adjacent is the side next to the one your taking the angle from and opposite is the remaining side, which is opposite the angle.

I have other posts on trigonometry which explain this in more detail which you should be able to find using the search feature on the right hand side of the page.

hope this helped,

David