Solve for ? sin(x)=-0.4

Take the inverse sine of both sides of the equation to extract from inside the sine.
Evaluate .
The sine function is negative in the third and fourth quadrants. To find the second solution, subtract the solution from , to find a reference angle. Next, add this reference angle to to find the solution in the third quadrant.
Simplify the expression to find the second solution.
Remove the parentheses around the expression .
Simplify .
Multiply by .
Find the period.
The period of the function can be calculated using .
Replace with in the formula for period.
Solve the equation.
The absolute value is the distance between a number and zero. The distance between and is .
Divide by .
Add to every negative angle to get positive angles.
Add to to find the positive angle.
Subtract from .
List the new angles.
The period of the function is so values will repeat every radians in both directions.
, for any integer
Solve for ? sin(x)=-0.4