Angle Formula

What Are Angle Formulas?

The measurements of the angles are determined using the Angle Formula. Two rays that cross at the same point and are referred to as the angel’s arms are what make up an angle. The vertex of the angle is the name for the angle’s corner point. The amount of rotation between the two lines is referred to as the angle. Angles are expressed in radians or degrees.

The formulae for the angle created at the circle’s centre by two radii and an arc have been covered in this article. Let’s also concentrate on the trigonometric formulae for numerous angles and double angles. The Extramarkrs provide all the important information about the Angle Formula. 

Different types of Angles

Acute angle: An acute angle is any angle that is between 0 and 90 degrees, or higher than 0 and less than 90. 

Right angle: The angle that is exactly 90 degrees is referred to as a right angle.

Obtuse angle: An obtuse angle is one that is between 90 and 180 degrees, or higher than 90 and less than 180. 

An angle that is exactly 180 degrees in length is referred to as a straight angle.

Reflex angle: A reflex angle is an angle that is between 180 and 360 degrees, or more than 180 and less than 360. 

A complete angle, also known as a full rotation, is an angle that is exactly 360 degrees in length.

 Multiple Angle Formulas

Trigonometric functions frequently contain the many angles. Although it is impossible to directly obtain the values of many angles, their values can be computed by expanding each trigonometric function. The Eulers formula and Binomial Theorem are used to determine these numerous angles of the forms sin nx, cos nx, and tan nx, which are stated in terms of sin x, cos x, and simplify cos x.

List of Multiple Angle Formula 

Half Angle Formula 

sin x = 2 sin(x/2)cos(x/2) = (2 tan (x/2))/(1 + tan2(x/2))

cos x = cos2(x/2) – sin2(x/2) = 2cos2(x/2) – 1 = 1 – 2sin2(x/2) = (1 – tan2(x/2))/(1 + tan2(x/2))

tan x = (2 tan(x/2))/(1 – tan2(x/2))

sin(x/2) = √((1 – cos x)/2)

cos(x/2) = √((1 + cos x)/2)

tan(x/2) = √((1 – cos x)/(1 + cos x)) 

Double Angle Formula: 

sin 2x = 2sin x cos x = (2 tan x)/(1 + tan 2x) 

cos 2x = cos 2x – sin 2x = 2cos 2x – 1 = 1 – 2sin 2x = (1 – tan 2x)/(1 + tan 2x)

tan 2x = (2 tan x)/(1 – tan 2x) 

 Triple Angle Formula: 

sin 3x = 3sin x – 4sin3x

cos 3x = 4cos3x – 3cos x

tan 3x = (3tan x – tan3x)/(1 – 3tan2x)

  Double Angle Formulas

Triangle connections involving angles, lengths, and heights are the subject of trigonometry. It provides a number of useful identities that can be used to comprehend and deduce the numerous scientific equations and formulas.This article examines a few particular varieties of trigonometric equations known as the “double Angle Formula.” They get this name because they employ double angle trigonometric functions.

Trigonometric ratios of double angles (2θ) are expressed in terms of trigonometric ratios of single angles (θ) using double Angle Formula. The Pythagorean identities are used to create certain alternative formulae, while the double Angle Formula are special instances of (and are thus derived from) the sum formulas of trigonometry. In each of the aforementioned sum formulas, we may get the double Angle Formula of sin, cos, and tan by changing A = B. We also arrive at a few other formulae by applying the Pythagorean identities.

the double Angle Formula of sin, cos, and tan are,

sin 2A = 2 sin A cos A (or) (2 tan A) / (1 + tan2A)

cos 2A = cos2A – sin2A (or) 2cos2A – 1 (or) 1 – 2sin2A (or) (1 – tan2A) / (1 + tan2A)

tan 2A = (2 tan A) / (1 – tan2A) 

 What is Central Angle of Circle Formula?

The central angle of a circle formula is used to calculate the angle between two circle radii.Another way to describe a central angle is as an angle that is subtended by the circle’s arc and its two centre radii. The radius vectors make up the arms of the central angle. To compute the central angle, we need the radius of the circle and the measurement of the length of the arc that subtends the central angle at the centre.

Central angle,

 θ = (Arc length × 360º)/(2πr) degrees 


Central angle,

 θ = Arc length/r radians,

 r is the radius of the circle.

Examples Using Angle Formulas

1 Jill has a circular section with a radius of 9 units and an arc length of 7 units. Using the angles formulae, determine the segment’s angle.

Arc length =  7π (given)                   

Radius = 9 units(given)                  

Using Angles Formulas,                                      

Angle = (Arc Length × 360o)/2π r

Angle = (7π × 360o)/2π × 9}                                                                

= 140o degrees.

Therefore, the angle of the segment is 140o

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FAQs (Frequently Asked Questions)

1. What does Angle Formula Mean?

The measurements of the angles are determined using the Angle Formula. A figure called an angle is made up of two crossing rays that share a terminal. These rays are referred to as the angle’s arms. The vertex of the angle is the name for the angle’s corner point. The amount of rotation between the two lines is referred to as the angle. The Angle Formula covers a variety of issues, including the central angle of a circle and multiple angles.

2. What is the Angle Formula for a Double Angle?

cos(2a) = cos2(a)–sin2(a) = 2cos2(a) −1 = 1 − 2sin2(a)

sin(2a) = 2sin(a) cos(a)

tan(2a) = 2tan(a) ÷ 1−tan2(a)