Common Trigonometry Mistakes
Example: Value of inverse cosine

The Goal



The Mistake

Find the mistake:


(Roll the mouse over the math to see a hint in red)

The Correction


(Roll the mouse over the area above to see the correction in blue)

An Explanation

The range for inverse cosine is the interval from 0 to π. Cosine takes on negative values between π/2 and π. Students should learn the values of the inverse trigonometric functions at nice values - visit Trigonometric Facts to help learn these values.

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