# Arctan Formula

## What is Arctan?

In trigonometry mathematics, every function has an inverse and arctan is the inverse of the tangent function. Arctan is also referred to as the tan-1. Arctan x is used to find the angle. The tangent on the other hand is described as the ratio of the opposite side to the adjacent side of a particular angle of a right-angled triangle. Arctan formula is used to identify an angle.

### What is the Arctan Formula?

A fundamental arctan formula is written as:

• θ =  arctan(opposite ÷ adjacent)

Other arctan formulas are as given below:

• arctan(x) = 2arctan (x/1+√1+x2)

• arctan(x) = ∫x0 1/z2+1dz;|x|≤1

• ∫arctan(z) dz = z arctan(z) – 1/2 ln(1+z2) + C

Arctangent formulas for π are as given below:

• π/4 = 4 arctan(1/5) - arctan(1/239)

• π/4 = arctan(1/2) + arctan(1/3)

• π/4 = 2 arctan(1/2) - arctan(1/7)

• π/4 = 2 arctan(1/3) + arctan(1/7)

• π/4 = 8 arctan(1/10) - 4 arctan(1/515) - arctan(1/239)

• π/4 = 3 arctan(1/4) + arctan(1/20) + arctan(1/1985)

• π/4 = 24 arctan(1/8) + 8 arctan(1/57) + 4 arctan(1/239)

### Solved Examples Using Arctan Formula

The arctan formula can be thoroughly understood for use and application referring to solved examples below.

Example:

In the right-angled triangle PQR, the base of which measures 17 cm and the height is 9cm. Determine the base angle.

Solution:

To calculate: base angle

How: Using arctan formula

θ = arctan(9 ÷ 17)

= arctan(0.52)

θ = 27.47 degrees or 270

Example:

Find out the value of θ, given that the base of the triangle ABC is 24 ft and the height is 11 ft

Solution:

arctanθ = 11 ÷ 24 =0.24

arctanθ = 24.60

θ = 240

Q1. What is the Use of Arctan?

Answer: The arctan is trigonometric functions and these functions are used to describe values associated with right triangles. Practically, we apply these functions in order to resolve the distance or height of the object which is otherwise complex to measure.

Apart from, it has practical application in different fields like constructing, architecture, landscaping, engineering, physics, and other mathematical and scientific areas.

In addition, this is resolute taking into account the measure of one angle (not right angle) as well the ratio of two sides of the triangle. Apart from, we identify trigonometric functions by the sides of the triangle that are used in the ratio of these formulas:

Sine = opposite / hypotenuse