What is the value of i²³?

Express 1/√2 - i in the form of a + bi.

Convert the spherical - coordinate equation Φ = 60 degrees to its rectangular - coordinate equation.

Determine the radius of the sphere whose equation is:

Find the distance between the lines, 3x + y - 12 = 0 and 3x + y - 4 = 0.

Point P(x, y) moves with a distance from point (0, 1) one-half of its distance from line y = 4, the equation of its locus is:

Determine the radius of the sphere whose equation is x² + y² + z² - 2x + 8y + 16z + 65 = 0.

Find the perimeter of a regular pentagon that is circumscribed by a circle with radius r = 10 cm