Cos 0 Degrees – Value, Formula, Periodicity & Solved Examples

The value of cos 0 degrees is 1. In a right-angled triangle, the cosine (cos) of an angle is the ratio between the side next to the angle (adjacent side) and the longest side (hypotenuse). Cos is one of the six main trigonometric functions we use to understand angles and sides in triangles.

We can also use the unit circle to understand this. At 0 degrees, the point lies on the positive x-axis, and the cosine value (x-coordinate) is 1.

So, cos 0 = 1 because the adjacent side is the same as the hypotenuse in this case.

What is Cos 0 Degree?

Cos 0 degree is the value of the cos trigonometric function for an angle equal to 0 degrees. Cosine of a zero-degree angle is formally written as cos 0° and the exact value of the cos 0 degree is 1.

Cos 0 value in fractions

Cos 0 value is the integer 1, so in fraction we can write it as 1/1

Cos 0 value in Decimals

Cos 0 value in fractions is 1/1 so in decimals, it is 1.0

Cos 0 value in Radians

We know that when we convert degrees to radians,

We can find the value of cos 0 degrees in two ways:

1. Cos 0 Degree value using Unit Circle
2. Cos 0 Degree value using Trigonometric Functions

Cos 0 Degree value using Trigonometric Functions

The trigonometric foundations can also be used to calculate the cosine of angle zero degrees. According to Pythagorean trigonometric identity, the cos function can be represented by the sine function.

We can find the value of cos(0°) using a trigonometric identity.

We know that:

sin(0°) = 0

Using the identity:

cos²θ = 1 − sin²θ

Substitute θ = 0°:

cos²(0°) = 1 − sin²(0°)

cos²(0°) = 1 − 0² = 1

cos(0°) = √1 = 1

Therefore, the value of cos(0°) is 1.

Cos 0 Degree value using Unit Circle

By using the unit circle, we can find the value of cos 0 degrees:

Using the unit circle, the cosine of an angle is defined as the x value of the endpoint on the unit circle of an arc of length . Cos 0 degrees is the value of the x-coordinate of the point on the unit circle after a 0-radian (counterclockwise) rotation from the positive x-axis (right). Because there has been no rotation, the point on the circle remains on the x-axis. Because the radius of the unit circle is one,

What is Cos 0 Degree Formula?

The cos function has the formula

When x = 0

Adjacent side length = hypotenuse length

As a result

Cos value Chart and Table

Cos value chart is shown below:

Cos value table is given below:

Degree
	1
	0
	-1
	0

Learn about Value of Cos 360

Periodicity of Cos Values

The cosine function is a periodic trigonometric function. A periodic function in mathematics is a function that repeats itself indefinitely in both directions. Consider the basic cosine function . The following graph shows its plot.

When we look at the cosine function from x = 0 to x = we see an interval of the graph that is repeated in both directions, that’s why the cosine function is a periodic function. In period, value is repeated.

Properties of Cos 0°

Value of Cos 0°:
cos 0° = 1
The cosine of 0 degrees is exactly 1.

Right-Angle Triangle Definition:
The ratio of the adjacent side to the hypotenuse is known as the cosine.

 Since the lengths of these two sides are equal at 0°, the ratio is 1.

Definition of a Unit Circle:

The coordinates at 0° on the unit circle are (1, 0).

 Since the x-coordinate of an angle is its cosine, cos 0° = 1.

An Even Function Is the Cosine:

cos(−θ) = cos(θ)

Thus, cos(−0°) = cos(0°) = 1.

Periodicity:
Cosine is a periodic function with a period of 360° or 2π radians.
That means:
cos(0°) = cos(360°) = cos(720°) = 1

Always Positive in the First Quadrant:
Since 0° lies in the first quadrant, cosine is always positive here.

Graph Behavior:
On the graph of cos(θ), the value starts at 1 when θ = 0°.

What are Trigonometric Ratios?

Trigonometric ratios are special values that show the relationship between the sides of a right-angled triangle based on a given angle (usually written as θ, "theta").

In a right triangle:

• The hypotenuse is the longest side (opposite the right angle).
• The base is the side next to the angle θ.
• The perpendicular is the side opposite angle θ.

There are six trigonometric ratios, and they are defined using these sides:

• Sin θ (Sine) = Perpendicular ÷ Hypotenuse
  It shows how tall the triangle is compared to its longest side.
• Cos θ (Cosine) = Base ÷ Hypotenuse
  It shows how wide the triangle is compared to the hypotenuse.
• Tan θ (Tangent) = Perpendicular ÷ Base
  It compares height to width.
• Cot θ (Cotangent) = Base ÷ Perpendicular
  It’s the opposite of tangent.
• Sec θ (Secant) = Hypotenuse ÷ Base
  It’s the flip of cosine.
• Cosec θ (Cosecant) = Hypotenuse ÷ Perpendicular
  It’s the flip of sine.

Trigonometric Ratios Table

The Trigonometric Ratios Table lists the standard values of sine, cosine, tangent, and other trigonometric functions for commonly used angles like 0°, 30°, 45°, 60°, and 90°. It helps in quickly solving trigonometric problems without using a calculator. These values are essential for geometry, trigonometry, and competitive exams.

Angles (in Degrees): 0°, 30°, 45°, 60°, 90°, 180°, 270°, 360°

Angles (in Radians): 0, π/6, π/4, π/3, π/2, π, 3π/2, 2π

Angle (°)	sin	cos	tan	cot	cosec	sec
0°	0	1	0	Not Defined	Not Defined	1
30°	1/2	√3/2	1/√3	√3	2	2/√3
45°	1/√2	1/√2	1	1	√2	√2
60°	√3/2	1/2	√3	1/√3	2/√3	2
90°	1	0	Not Defined	0	1	Not Defined
180°	0	-1	0	Not Defined	Not Defined	-1
270°	-1	0	Not Defined	0	-1	Not Defined
360°	0	1	0	Not Defined	Not Defined	1

Solved Examples of Cos 0 Degree

Example 1: Determine the value of

Solution: According to trigonometric identities

So the value of is

Example 2: Determine the value of if is 1

Solution:

= 1

Example 3: Find the value of the expression √3 (sin 60 + cos 30) + sin 90 + cos 0 + sin 30 + cos 60

Solution: We know the standard trigonometric values:

• sin 60 = √3/2
• cos 30 = √3/2
• sin 90 = 1
• cos 0 = 1
• sin 30 = 1/2
• cos 60 = 1/2

Now substitute the values into the expression:

√3 (sin 60 + cos 30) + sin 90 + cos 0 + sin 30 + cos 60
= √3 (√3/2 + √3/2) + 1 + 1 + 1/2 + 1/2
= √3 (2√3/2) + 1 + 1 + 1
= √3 × √3 + 3
= 3 + 3 = 6

Final Answer: 6

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If you are checking Cos 0 degree article, also check related maths articles:
Cosine Function	Cosine Rule
Derivative of Cos x	Value of Cos 180
Value of Cos 120	Sin Cos Tan Values

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