why there is a nee d to find sin , cos&tan of the triangle. & what its application?

Answer 1

Well, to beging with a triangle does not have a tan, cos or sin. These are characteristics of a given angle.
These quantities are essential for trigonometry. Trigonometry is the study of triangles and their use of measuring distances. For exaple you can use trigonometry to measure the height of a building or a mountain. You can even use it to measure the distance to near by stars.

Answer 2

Sine, cosine and tangent of angles are simply the ratios between the length of certain legs of a right triangle. Given a right triangle (one angle must be 90º angle) the sine of an angle is the ratio between the side opposite that angle and the hypotenuse (longest side). The cosine of the angle is the ratio between the side closest to the angle and the tangent is the ratio between the opposite and adjacent (closest) side.

With this information, one only needs to know two pieces of information about a right triangle in order to completely describe it. Any unknown information can be determined based on two data points.

Right triangles describe many real world situations. Some are obvious. For instance, if you want to install a guy wire on a telephone pole you can use a right triangle to determine how much wire is necessary. Others are not as obvious: right triangles can be used to describe the relationships between power and voltage in electricity.

Answer 3

Sin and Cos are both used in the field of Mechanics and are heavily involved with Newton's Laws of motion. Most mathematical functions use sin or cos in one way or another.

Tan is used regularly when taking the gradient of Graph's or TANgents to curves on a graph, hence the name TAN stands for Tangential.

Wait until you hit the hyperbolic functions called sinh cosh and tanh (and all the inverse functions and trig identities you'll have to learn - woo! glad I did all that stuff years ago)

Answer 4

These mathematical functions are the foundation/underpinnings for the mathematics area of trigonometry. Trig helps explain how global positioning satellites determine where you are on the globe, and how measurements thru space can be done (like the distance from earth to moon, or the distance across a river, or how long to cut that rafter for your house.).

(Of course you DON'T HAVE TO KNOW about trig; in much the same way you don't have to know or have any notion how a car manages to get you from point to point; after all who needs to know what a spark plug does to get your vehicle going?)

You don't have to know anything about saturated fats or cholesterol or LDL or HDL or how to read food labels for pertinent information. (I didn't pay much attention to any of these 2 decades ago; but when they became relevant I had the educational basis to read about and understand their significance.) So your study of trig is probably quite relevant to whatever career you've chosen; and even if it's not that relevant it gives you a basis for understanding a lot of other science.