The following are all angle measures, in degrees, whose cosine is −1 .Which is the principal value of arccos(−1) ?Choose 1 answer:(A) −540∘(B) −180∘(C) 180∘(D) 540∘
Q. The following are all angle measures, in degrees, whose cosine is −1 .Which is the principal value of arccos(−1) ?Choose 1 answer:(A) −540∘(B) −180∘(C) 180∘(D) 540∘
Identify principal value range: Identify the principal value range for arccosine function.The principal value for arccosine, or the inverse cosine function, is between 0 and 180 degrees.
Determine angle with cosine −1: Determine the angle whose cosine is −1 within the principal value range.The cosine of 180 degrees is −1, which is within the principal value range for arccosine.
Eliminate options not within range: Eliminate the options that are not within the principal value range. Options (A) −540 degrees and (D) 540 degrees are not within the principal value range of 0 to 180 degrees. Option (B) −180 degrees is also not within the principal value range. Therefore, these options are incorrect.
Choose correct answer: Choose the correct answer from the remaining options.The only option left that is within the principal value range and whose cosine is −1 is (C) 180 degrees.