Evaluate the following expressions. Give an exact answer in radians.

(a) ` \cos^(-1)(-\frac{1}{2}) = `  

(b) ` \cos^(-1)(1) = `  

(c) ` \cos^(-1)(-\frac{\sqrt{2}}{2}) = `  

Hint

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Box 1: Enter your answer as a number (like 5, -3, 2.2172) or as a calculation (like 5/3, 2^3, 5+4)
Enter DNE for Does Not Exist, oo for Infinity
Decimal values are not allowed
Trig functions (sin,cos,etc.) are not allowed

Box 2: Enter your answer as a number (like 5, -3, 2.2172) or as a calculation (like 5/3, 2^3, 5+4)
Enter DNE for Does Not Exist, oo for Infinity
Decimal values are not allowed
Trig functions (sin,cos,etc.) are not allowed

Box 3: Enter your answer as a number (like 5, -3, 2.2172) or as a calculation (like 5/3, 2^3, 5+4)
Enter DNE for Does Not Exist, oo for Infinity
Decimal values are not allowed
Trig functions (sin,cos,etc.) are not allowed