Given the inequality:
3sin(4x)>−23To solve this inequality, we must first solve the corresponding equation:
3sin(4x)=−23Solve:
Given the equation
3sin(4x)=−23- this is the simplest trigonometric equation
Divide both parts of the equation by 1/3
The equation is transformed to
sin(4x)=−29As right part of the equation
modulo =
True
but sin
can no be more than 1 or less than -1
so the solution of the equation d'not exist.
x1=4π+4asin(29)x2=−4asin(29)Exclude the complex solutions:
This equation has no roots,
this inequality is executed for any x value or has no solutions
check it
subtitute random point x, for example
x0 = 0
3sin(0⋅4)>−230 > -3/2
so the inequality is always executed