Mechanics of machine force analysis with analytical method

AI Thread Summary
The discussion focuses on understanding the calculation of an angle in a machine force analysis problem, specifically the result of -168.1 degrees. The confusion arises from the use of a comma in the inverse tangent function, which is clarified by the need for both dy and dx components to accurately determine the vector direction. The arctangent function, particularly atan2, is essential for resolving the full circle of slope. This method ensures correct angle determination in two-dimensional force analysis. Understanding these components is crucial for accurate mechanical analysis.
Pipsqueakalchemist
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So I was looking at this example problem in my textbook and I don’t understand how they got -168.1 degrees. The part I’m confused with is the first part of the 2nd picture, there’s a coma in the inverse tan, I don’t know what that means.

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To resolve the full circle of slope or vector direction, the arctangent function needs both the dy and the dx components as parameters.
https://en.wikipedia.org/wiki/Atan2
 
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