a) Use a calculator to find, in radians correct to 3 significant figures, the principal value of

i) tan⁻¹ (0.4)

ii) tan⁻¹ (−0.4)

iii) sin⁻¹ (2/3)

iv) sin⁻¹ (−2/3)

v) cos⁻¹ (0.62)

vi) cos⁻¹ (−0.62).

b) What do you notice about your answers to (a) (i) and (a)(ii)?

c) What do you notice about your answers to (a)(iii) and (a)(iv)?

d) What do you notice about your answers to (a)(v) and (a)(vi)?