The arctan function represent the inverse of the tangent function. If the tangent of a number is a second number, the arctan of the second number is the first number. The function is useful when solving trigonometric problems. If you know the two shorter lengths in a right-angled triangle, the arctan of the ratio between them equals the angle between one of them and the hypotenuse.
Search your calculator for the arctan button, which will be marked as either "arctan," "atan" or "tan-1." If the calculator has an arctan button, press it and skip to Step 3. If it doesn't, continue to Step 2.
Press the calculator's "shift," "2nd" or "function" key, and then press the "tan" key.
Type the number whose arctan you want to find. For this example, type in the number "0.577."
Press the "=" button. The number's arctan will appear. The arctan of 0.577, for instance, is approximately 30.
About the Author
Ryan Menezes is a professional writer and blogger. He has a Bachelor of Science in journalism from Boston University and has written for the American Civil Liberties Union, the marketing firm InSegment and the project management service Assembla. He is also a member of Mensa and the American Parliamentary Debate Association.