If cos θ = 5/13, use the pythagorean identity to find sin θ. 13/13 12/13 12/5 5/13

a complex number is a number that can be expressed in the form a + bi, where a and b are real numbers, and i is a solution of the equation x2 = −1. because no real number satisfies this equation, i is called an imaginary number. has no real solution, since the square of a real number cannot be negative.