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How to Use Trigonometric Functions in GeoGebra

GeoGebra has the built-in functions sin(<x>), cos(<x>) and tan(<x>) for calculating the sine, the cosine and the tangent of angles.

GeoGebra uses the names asin(<x>) and acos(<x>), for the inverse functions sin 1(x) and cos 1(x) for x in the interval [1, 1], and atan(<x>) for tan 1(x) for any x. Use the inverse functions to calculate the angles of a right triangle when you already know two or all the side lengths, by typing the expression directly in Algebra View or CAS.

When you input angles measured in degrees, you have to use the symbol (keyboard shortcut alt+o).

Note! If you try to insert a value less than 1 or greater than 1, GeoGebra will return a number containing the letter i. This indicates that you have received a complex solution. Unless you know that complex solutions are fine for your problem, this solution indicates that you input something wrong.

Note! In some versions of GeoGebra, angles in Algebra View are by default measured in degrees, while angles in CAS are measured in radians. If you want CAS to use degrees, use the commands asind(<x>), acosd(<x>), and atand(<x>), which are the regular commands with a d at the end of the command name.

You can also get the answer in degrees quickly by dividing your answer by or by the string deg, such as asin(<x>)/. It may seem strange to divide by , but it works!

GeoGebra Instruction 1

Trigonometric Expressions in Algebra View

1.
Open Algebra View under GeoGebra icon View in GeoGebra icon Menu.
2.
Type the expression and press Enter.

GeoGebra Instruction 2

Trigonometric Expressions in CAS

1.
Open CAS under GeoGebra icon View in GeoGebra icon Menu.
2.
Type the expression. If you press Enter you get the exact answer. If you press Symbolic Evaluation GeoGebra icon you also get the exact answer. If an exact value does not exist, GeoGebra writes the answer in radians. Therefore, press Numeric Evaluation GeoGebra icon to get the answer as a decimal number.

Screenshot of GeoGebra showing different computations with trigonometric functions

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