Question

how I can say that it is sin,tan or cos

Answer 1

Hello,


Sin means sine.
Cos means cosine
Tan means Tangent.

This can be identified using the right triangle sides.
We know that there are three parts in a right triangle
They are
Perpendicular (p)
Base (b)
And, hypotenuse (h)

Now
These trigonometric ratios are to be learnt.
There is an Easy process. I will tell you at last of the answer.

See

Sin = perpendicular/ hypotenuse

Cos = base/ hypotenuse

Tan = perpendicular /base

They have their reciprocal also.
Reciprocal of :-
Sin is cosec (cosecant)
Cos is sec (secant)
Tan is cot (cotangent)

Their values are also reciprocals of their parent
For example :-

Cosec = hypotenuse /perpendicular

Sec = hypotenuse /base

Cot = base/ perpendicular

Now

Suppose their is a right triangle with h = 5
P = 4 and b =3

So,
SinC (in figure) = 4/5
CosC = 3/5
And Tan C = 4/3

Now,

The easier way to remember this :-

Remember this line
Some People Having, Curly Brown Hair, Turns Permanently Blue.

Now,
Adjust the capital words ( first letter of each word as follows
S = P/H
C = B/H
T= P/B

here,
S is sin, c is cos and t is tan
Also, p is perpendicular, b is base and h is the hypotenuse of the right triangle.


This way you can easily identify sin, cos, tan, cosec, sec and cot.


Hope this will be helping you....