Find the exact value of the expressionGive answer in Degrees

Find the exact value of the expression/Give answer in Degrees in the interval (-90, 180) degrees. cos^-1(-sqrt3/2)

Find the exact value of the expression/Give answer in Radians in the interval (-pi/2, pi) co^1(-sqrt2/2)

1) exact value of the expression/Give answer in Degrees in the interval (-90, 180) degrees. cos^-1(-sqrt3/2)

y = cos^-1(-sqrt3/2)

cosy = -sqrt(3)/2

Now y lies in IVrth or Ist or IInd quadrant.

So,cos is -ve in IIndquadrant

So, cosy = -sqrt(3)/2 ----> y = pi -pi/6 = 5pi/6

So,cos^-1(-sqrt3/2) = 5pi/6 =150 deg

2) Please expalin whether it i cot or cos : (-pi/2, pi) co^1(-sqrt2/2)