The angle with tangent value of 1 occurs when opposite = adjacent, which happens at 45° or 4π radians.
tan−1(1)=4π
For cosine value of −23, the negative sign indicates the 2nd or 3rd quadrant. The range of inverse cosine is [0,π], so the 2nd quadrant is used.
Since cos(6π)=23
In the 2nd quadrant:
π−6π=65π
cos−1(−23)=65π
The sine value of 21 is a standard value:
sin(6π)=21
sin−1(21)=6π
Adding all three values:
4π+65π+6π
Converting to common denominator of 12:
123π+1210π+122π
=1215π
=45π
Therefore, the value is 45π.