21sin^2x-4sinx-1=0

Solution for 21sin^2x-4sinx-1=0 equation:

Simplifying
21sin2x + -4sinx + -1 = 0

Reorder the terms:
-1 + -4insx + 21in2sx = 0

Solving
-1 + -4insx + 21in2sx = 0

Solving for variable 'i'.

Move all terms containing i to the left, all other terms to the right.

Add '1' to each side of the equation.
-1 + -4insx + 1 + 21in2sx = 0 + 1

Reorder the terms:
-1 + 1 + -4insx + 21in2sx = 0 + 1

Combine like terms: -1 + 1 = 0
0 + -4insx + 21in2sx = 0 + 1
-4insx + 21in2sx = 0 + 1

Combine like terms: 0 + 1 = 1
-4insx + 21in2sx = 1

Reorder the terms:
-1 + -4insx + 21in2sx = 1 + -1

Combine like terms: 1 + -1 = 0
-1 + -4insx + 21in2sx = 0

The solution to this equation could not be determined.