Trigonometric Table - Formula | Trigonometry Ratio Table (2023)

The trigonometric table helps in finding the values of trigonometric ratios for standard angles such as 0°, 30°, 45°, 60°, and 90°. Trigonometric table comprises trigonometric ratios – sine, cosine, tangent, cosecant, secant, cotangent. These ratios, in short, are written as sin, cos, tan, cosec, sec, and cot. The values of trigonometric ratios of standard angles in a trig table are essential in solving trigonometry problems.

Trigonometry deals with the measurement of angles and problems related to angles. The term trigonometry is derived from a Latin word. Trigonometry makes use of the relationship between the angles and sides of a triangle.

What is Trigonometric Table?

The Trigonometric Table is simply a collection of the values of trigonometric ratios for various standard angles including 0°, 30°, 45°, 60°, 90°, sometimes with other angles like 180°, 270°, and 360° included, in a tabular format. Because of patterns existing within trigonometric ratios and even between angles, it is easy to both predict the values of the trigonometry table and use the table as a reference to calculate trigonometric values for various other angles. The trigonometric functions are namely sine function, cosine function, tan function, cot function, sec function, and cosec function.

Trigonometric Values

To remember this easily remember the word "SOHCAHTOA"!

• SOH

Sine = Opposite / Hypotenuse

• CAH

Cosine = Adjacent / Hypotenuse

• TOA

Tangent = Opposite / Adjacent

Standard Angles in a Trigonometric Table

The values of trigonometric ratios for the angles 0°, 30°, 45°, 60°, and 90° in a trigonometry table are commonly used to solve the trigonometry problems. These values are associated with the measurement of the lengths and the angles of a right-angle triangle. Thus, 0°, 30°, 45°, 60°, and 90° are called the standard angles in trigonometry.

Trigonometry Table for Standard Angles

The trigonometric table is simply a collection of values of trigonometric functions of various standard angles including 0°, 30°, 45°, 60°, 90°, along with with other angles like 180°, 270°, and 360° included, in a tabular format. It is easy to predict the values of the trig ratios in a trigonometric table and to use the table as a reference to calculate trigonometric values for various other angles, due to the patterns existing within trigonometric ratios and even between angles.

The table consists of trigonometric ratios – sine, cosine, tangent, cosecant, secant, and cotangent. In short, these ratios are written as sin, cos, tan, cosec, sec, and cot. It is best to remember the values of the trigonometric ratios of these standard angles.

Using the above table, values of sin π/6, cos π/6, tan π/6, sin π/4, cos π/4, tan π/4, sin π/3, cos π/3, tan π/3, sin π/2, cos π/2, and tan π/2 in radians could be easily found out. A trigonometric table has wide application in fields like science and engineering.

A few key points that can be noted in the trigonometric table are,

• The values for complementary angles present like 30° and 60° in a trigonometric table can be computed using complementary formulas for the various trigonometric ratios.
• The value for some ratios in a trig table is given as ∞ or "not defined". The reason for this is that while computing the values, a "0" appears in their denominator, so the value becomes undefined and is said to be equivalent to infinity.
• There is a sign change in the values in various places under 180°, 270°, etc for values of some trig ratios in a trigonometric table. This is due to the change in the quadrant.

How to Learn Trigonometric Table?

The trigonometric table might seem complex at first, but it can be learned easily by only the values of sine for the 8 standard angles. Before generating the table, there are few formulas that must be followed as given below,

• tan x = sin x/cos x
• cosec x = 1/sin x
• sec x = 1/cos x
• cot x = 1/tan x

Given below are the steps to create and remember a trigonometric table.

• Step 1: Create a table with the top row listing the angles such as 0°, 30°, 45°, 60°, 90°, and write all trigonometric functions in the first column such as sin, cos, tan, cosec, sec, cot.
• Step 2: Determining the value of sin: Write the angles 0°, 30°, 45°, 60°, 90° in ascending order and assign them values 0, 1, 2, 3, 4 according to the order. So, 0° ⟶ 0; 30° ⟶ 1; 45° ⟶ 2; 60° ⟶ 3; 90° ⟶ 4. Then divide the values by 4 and square root the entire value. 0° ⟶ √0/2; 30° ⟶ 1 /2; 45° ⟶ 1/ √2; 60° ⟶ √3/2; 90° ⟶ √(4/4). This gives the values of sine for these 5 angles. Now for the remaining three use:

sin (180° − x) = sin x
sin (180° + x) = -sin x
sin (360° − x) = -sin x

This means,
sin (180° − 0º) = sin 0º
sin (180° + 90º) = -sin 90º
sin (360° − 0º) = -sin 0º

• Step 3: Determining the value of cos: sin (90° – x) = cos x. Use this formula to compute values for cos x. For example, cos 45° = sin (90° – 45°) = sin 45°. Similarly, cos 30° = sin (90° - 30°) = sin 60°. Using this, you can easily find out the value of cos function as,

• Step 4: Determining the value of tan: (tan x = sin x/cos x). Hence, the value of tan function can be generated as,

• Step 5: Determining the value of cot: (cot x = 1/tan x). Use the relation to generate the cot function as,

• Step 6: Determining the value of cosec: (cosec x = 1/sin x)

• Step 7: Determining the value of sec: (sec x = 1/cos x)

The following trigonometric table covers the value of trigonometric ratios for all basic angles ranging from 0º to 360º.

Trick to Remember Trigonometric Table

Let us learn the one-hand trick for remembering the trigonometric table easily! Designate each finger the standard angles as shown in the image. For filling the sine values in the trigonometry table, we will include counting of the fingers, while for the cos table we will simply fill the values in reverse order.

• Step 1: For the sine table, count the fingers on the left side for the standard angle.
• Step 2: Divide the number of fingers by 4
• Step 3: Take out the square root of the ratio.

Example 1: For sin 0°, there are no fingers on the left-hand side, therefore we will take 0. Dividing the zero by 4 we get 0. Taking the square root of the ratio we would get the value of sin 0° = 0

Example 2: For sin 60°, there are 3 fingers on the left-hand side. Dividing 3 by 4 we get (3/4). Taking the square root of the ratio √(3/4) we would get the value of sin 60° = √3/2.

Similarly, we can find out values for sin 30°, 45°, and 90° to fill the table.

In order to complete the cos table, simply fill in the values of sine in a reverse manner. For tan values, create the ratios by taking numerators of sine and cos values of the corresponding angle.

Given below is a list of trigonometric formulas that would help you memorize the trigonometric table, based on the relationship between different trigonometric ratios.

sin x = cos (90° – x)
cos x = sin (90° – x)
tan x = cot (90° – x)
cot x = tan (90° – x)
sec x = cosec (90° – x)
cosec x = sec (90° – x)
1/sin x = cosec x
1/cos x = sec x
1/tan x = cot x

Trigonometry Table in Radians

The trigonometric table for standard angles below presents the values of trigonometric ratios for the measure of angles given in radians.

☛ Related Topics:

• Trigonometry Formula
• Trigonometric Identities
• Trigonometric Ratios

Important Notes on Trigonometric Table

1. Trigonometric values are based on the three major trigonometric ratios: Sine, Cosine, and Tangent.
   Sine or sin θ = Side opposite to θ / Hypotenuse
   Cosines or cos θ = Adjacent side to θ / Hypotenuse
   Tangent or tan θ = Side opposite to θ / Adjacent side to θ

2. 0°, 30°, 45°, 60°, and 90° in a trigonometric table are called the standard angles in trigonometry.

3. The angle values of trigonometric functions cotangent, secant, cosecant in a trigonometric table, can also be calculated using these standard angles values of sine, cosecant, tangent.

4. All the higher angle values of trigonometric functions such as 120°, 390°, .... can be easily calculated from the standard angle values in a trigonometry table.

FAQs on Trigonometric Table

What is the Trigonometric Table?

Trigonometric table or sin cos table gives the values of trigonometric functions for the standard angles such as 0°, 30°, 45°, 60°, and 90°, in a tabulated manner.

What are the Standard Angles in a Trigonometric Table?

The angles 0°, 30°, 45°, 60°, and 90° in a trigonometric table are called standard angles, and the trigonometric values for these standard angles are commonly used to solve the trigonometry problems. These values are associated with the measurement of lengths and angles of the right-angle triangle.

What Does the Infinity Value of the Trigonometric Ratio in the Trigonometry Table Mean?

Undefined values in a trigonometric table are often given an infinity (∞) value because the value is such large that there is no definite value to assign at this point.

What are Trigonometric Functions and their Types Used In Trig Table?

Trigonometric functions are defined as the functions of an angle of a right-angled triangle. There are 6 basic types of trigonometric functions or ratios used in the trigonometric table,

• Sin function
• Cos function
• Tan function
• Cot function
• Cosec function
• Sec function

How to Find the Value of Trigonometric Functions Given in Trigonometric Table?

All the trigonometric functions in a trigonometric table are related to the ratios of sides of the triangle and their values can be easily found by using the following relations:

• sinθ = Opposite/Hypotenuse
• cosθ = Adjacent/Hypotenuse
• tanθ = Opposite/Adjacent
• cotθ = 1/tanθ = Adjacent/Opposite
• cosecθ = 1/sinθ = Hypotenuse/Opposite
• secθ = 1/cosθ = Hypotenuse/Adjacent

What are the Six Basic Trigonometric Functions in Trigonometric Table?

The six basic trigonometric functions in the trigonometric table are Sine, Cosine, Tangent, Secant, Cotangent, and Cosecant function.

How Does a Trigonometric Table Work?

The trigonometric ratios table helps us to find the values of trig ratios for standard angles such as 0°, 30°, 45°, 60°, and 90°. It comprises trigonometric ratios of sine, cosine, tangent, cosecant, secant, cotangent. These ratios are written in short as sin, cos, tan, cosec, sec, and cot.

Who Invented Trigonometry Table?

The Greek astronomer Hipparchus (127 BC) is believed to be the first to make a table of trigonometric functions (based on the chords in a circle).

What is the Easiest Way to Learn Trigonometric Tables?

To learn the one-hand trick for remembering the trigonometric table easily, designate each finger the standard angles. For filling the sine table we will include counting of the fingers. For the cos table, we will simply fill the values in reverse order.

• Step 1: To find the values of sine functions in a trigonometric table, count the fingers on the left side for the standard angle.
• Step 2: Divide this number of fingers by 4.
• Step 3: Take out the square root of the ratio to find the final sine value.

For example, For sin 0°, there are no fingers on the left-hand side, therefore we will take 0. Dividing the zero by 4 we get 0. Taking the square root of the ratio we would get the value of sin 0° = 0

Similarly, we can find out values for the sine ratio of other angles to fill the table. For tan, divide the value obtained for sin function by the value obtained for cos function.

What is the Use of a Trigonometry Table?

A trigonometric table is used to find the value of any trigonometric ratio for a given angle. The basic values of trig ratios for standard angles given in a trigonometry table can be used in the calculation of trigonometric ratios of other angles. These values find application in fields like engineering, architecture, etc.