# How to use trigonometric functions

Trigonometry functions - introduction

The main functions in trigonometry are Sine, Cosine and Tangent. They are simply one side of a right-angled triangle divided by another. For any angle " ? ": (Sine, Cosine and Tangent are often abbreviated to sin, cos and tan.). Learn how to use trig functions to find an unknown side length in a right triangle. Google Classroom Facebook Twitter. Email. Solving for a side in a right triangle using the trigonometric ratios. Solving for a side in right triangles with trigonometry.

There are six functions that are the core of trigonometry. There are three primary ones that you need to understand completely:. The other three are not used as often and can be gunctions from the three primary functions.

Because they can easily be derived, calculators and spreadsheets do not usually have them. Consider the right triangle above. For each angle P or Q, there are six functions, each function is the ratio of two sides of the triangle. The only difference between the six functions is which pair of sides we use.

In the following trigonomettic a is the length of the side a djacent to the angle x in question. In the following table, note how each function is the reciprocal of one of the basic functions sin, cos, tan. Because the functions are a ratio of two side lengths, they always produce the same result for a given angle, regardless of the size of the triangle.

In the figure above, drag the point C. Note how the ratio of the opposite side to the hypotenuse does not change, trigonomertic though their lengths do. Hkw is always 0. Remember: When you apply a trig function to a given functiins, it always produces the same result. See Inverse trigonometric functions. On calculators and spreadsheets, the inverse functions are sometimes written acos x or cos -1 x.

The six functions can also be defined in a rectangular coordinate system. For more on this see Trigonometry functions how to turn on 3g on samsung galaxy note large and negative angles.

The functions can be graphed, and some, notably the SIN function, produce functios that frequently occur in nature. For example see the graph of the SIN function, often called a sine wave, above.

For more see Graph how to use trigonometric functions the sine function Graph of the cosine function Graph of the tangent function.

Each of the functions can be differentiated in calculus. The result is another function trigonometricc indicates its rate of change slope at a particular values of x.

Using Trigonometric Functions in Excel

Aug 20,  · Excel contains a variety of trigonometric functions: The inverse functions are those usually denoted with a superscript -1 in math (i.e. ASIN is the Excel function for sin-1). These will return an angle given a sine value (or cosine, tangent, etc.). The “Miscellaneous” column contains functions that are useful in trigonometric calculations. Excel offers a number of built-in functions that deal with trigonometry. You can use these trig functions to solve complex trigonometric expressions. The main thing you need to consider while solving trigonometric expressions is that Excel performs the calculations considering angle value in radians and not in degrees. You might know that sin = cgsmthood.com, if you enter the formula SIN (90) in Excel, the result . Determining Trigonometric Function Values On The Calculator Using the TI 84 to find function values for sine, cosine, tangent, cosecant, secant, and cotangent. Calculators are able to determine trigonometric function values in degrees and radians. However, most calculators can .

Last Updated: January 26, References. This article was co-authored by our trained team of editors and researchers who validated it for accuracy and comprehensiveness. There are 13 references cited in this article, which can be found at the bottom of the page.

This article has been viewed , times. Learn more Right angled trigonometry is useful when dealing with triangles and is a fundamental part of trigonometry in general. Using the ratios that come from the right triangle, and understanding the application of the unit circle, you can solve a wide variety of problems involving angles and lengths.

Tips and Warnings. Related Articles. Method 1 of Set up a right triangle model. Trigonometry functions can be used to model real world situations involving lengths and angles.

The first step is to define the situation with a right triangle model. You know that the peak of the hill is meters above the base, and you know that the angle of the climb is 15 degrees. How far must you walk to reach the top? Sketch a right triangle and label the parts.

The vertical leg is the height of the hill. The top of that leg represents the peak of the hill. The angled side of the triangle, the hypotenuse, is the climbing trail. Identify the known parts of the triangle.

When you have your sketch and have labeled the parts of it, you need to assign the values that you know. On the problem of the hill, you are told that the vertical height is meters.

Mark the vertical leg of the triangle m. You are told that the climbing angle is 15 degrees. This is the angle between the base bottom leg of the triangle and the hypotenuse. You are asked to find the distance of the climb, which is the length of the hypotenuse of the triangle. Set up a trigonometry equation. Review the information that you know and what you are trying to learn, and choose the trigonometry function that links those together. For example, the sine function links an angle, its opposite side and the hypotenuse.

The cosine function links an angle, its adjacent side and the hypotenuse. The tangent function links the two legs without the hypotenuse. In the problem with the hill climb, you should recognize that you know the base angle and the vertical height of the triangle, so this should let you know that you will be using the sine function.

Solve for your unknown value. Use basic algebraic manipulation to rearrange the equation to solve for the unknown value. You will then use either a table of trigonometric values or a calculator to find the value of the sine of the angle that you know. Interpret and report your result. With any word problem, getting a numerical answer is not the end of the solution. You need to report your answer in terms that make sense for the problem, using the proper units.

Solve another problem for practice. Consider one more problem, set up a diagram, and then solve for the unknown length. Suppose a coal bed under your property is at a 12 degree angle and comes to the surface 6 kilometers away. How deep do you have to dig straight down to reach the coal under your property? Set up a diagram. This problem actually sets up an inverted right triangle.

The horizontal base represents the ground level. The vertical leg represents the depth under your property, and the hypotenuse is the 12 degree angle that slopes down to the coal bed.

Label the known and unknown values. You know that the horizontal leg is 6 kilometers 3. You want to solve the length of the vertical leg.

In this case, the unknown value that you want to solve is the vertical leg, and you know the horizontal leg. The trigonometry function that uses the two legs is the tangent. The lengths in this problem are in units of kilometers. Therefore, your answer is 1. The answer to the question is that you must dig 1. Method 2 of Read the problem with the unknown angle.

Trigonometry can also be used to calculate angle measurements. The procedure is similar, but the problem will ask for the measurement of an unknown angle. Consider the following problem: At a certain time of day, a foot high flag pole casts a shadow that is 80 feet long. What is the angle of the sun at this time of day? Remember that trigonometry problems are based on the geometry of right triangles. Sketch a right triangle to represent the problem, and label the known and unknown values.

For the flag pole problem, the vertical leg is the flag pole itself. Label its height feet. The horizontal base of the triangle represents the length of the shadow. Label the base 80 feet. The hypotenuse, in this case, does not represent any physical measurement but is the length from the top of the flag pole to the end of the shadow. This will provide the angle that you want to solve.

You need to review which parts of the triangle you know and which you need to solve. This will help you choose the correct trigonometry function to help find the unknown value. For the flag pole, you know the vertical height and the horizontal base, but you do not know the hypotenuse. The function that uses the ratio of the two legs is the tangent. Use the inverse trigonometry function to solve the angle measurement.

When you need to find the measure of the angle itself, you will need to use what is called the inverse trigonometry function. These are arcsin, arccos, and arctan. You will enter the value and then press the appropriate button, and you will get the measure of the angle.

Some calculators differ. On some, you will enter the value first, and then the arctan button. On some, you enter the arctan and then the value. You will need to determine which process works for your calculator. Interpret your result.

Because you were solving for an angle measurement, the unit of your result will be in degrees. Check to see that your answer makes sense. Based on this solution, the angle between the earth and the sun is At noon, the sun is directly overhead, which would be an angle of 90 degrees, so this solution seems reasonable. Set up another problem with an unknown angle. Anytime the angle measure is the unknown factor, you will use an inverse trigonometry function.