# How is law of cosine used in real life?

## How is law of cosine used in real life?

The law of cosines is used in the real world by surveyors to find the missing side of a triangle, where the other two sides are known and the angle opposite the unknown side is known. The law of cosines is also used whenever a triangle is involved.

## What is an oblique triangle?

An oblique triangle is any triangle that is not a right triangle. It could be an acute triangle (all threee angles of the triangle are less than right angles) or it could be an obtuse triangle (one of the three angles is greater than a right angle).

## What is the formula of cosine?

The cosine formulas using the law of cosines are, cos A = (b2 + c2 – a2) / (2bc) cos B = (c2 + a2 – b2) / (2ac) cos C = (a2 + b2 – c2) / (2ab)

## Why is law of cosines important?

The law of cosines is useful for computing the third side of a triangle when two sides and their enclosed angle are known, and in computing the angles of a triangle if all three sides are known.

## Why does ambiguous case occur?

The “Ambiguous Case” (SSA) occurs when we are given two sides and the angle opposite one of these given sides. The triangles resulting from this condition needs to be explored much more closely than the SSS, ASA, and AAS cases, for SSA may result in one triangle, two triangles, or even no triangle at all!

## What is one characteristic of a cosine function?

It has a period equal to pi. Its graph is symmetric about the y-axis. Its domain is between -1 and 1 and is inclusive.

## What is cosine law state?

Definition of law of cosines 1 : a law in trigonometry: the square of a side of a plane triangle equals the sum of the squares of the remaining sides minus twice the product of those sides and the cosine of the angle between them.

## When to use cosine rule?

Cosine Rule (The Law of Cosine) The Cosine Rule is used in the following cases: 1. Given two sides and an included angle (SAS) 2. Given three sides (SSS) The Cosine Rule states that the square of the length of any side of a triangle equals the sum of the squares of the length of the other sides minus twice their product multiplied by the cosine

## When to use law of sines vs law of cosines?

You use the law of cosines to relate the 3 sides of a triangle to one of the angles. So if you are given the 3 sides you can find the angle; or if you are given two sides and the included angle (the angle between the two sides) you can find the side opposite the included angle. The law of sines relates the angles and the sides opposite them.

## How do you prove the law of cosines?

Law of Cosines Definition. In Trigonometry,the law of Cosines,also known as Cosine Rule or Cosine Formula basically relates the length of the triangle to the cosines of one

• Formulas. Where a,b and c are the lengths of sides of a triangle.
• Proof. DA = b − acosC……(1) BD = a sinC……(2) Hence,the cosine law is proved.
• ## How to use cosine rule?

AC produced by an electromechanical alternator follows the graphical shape of a sine wave.

• One cycle of a wave is one complete evolution of its shape until the point that it is ready to repeat itself.
• The period of a wave is the amount of time it takes to complete one cycle.