Paragraph: Let a, b, c, d R . Then the cubic equation of the type a x^3+b x^2+c x+d=0 has either one root real or all three roots are real. But in case of trigonometric equations of the type a ^3 x+b ^2 x+c x+d=0 can possess several solutions depending upon the domain of x . To solve an equation of the type a +b =c . The equation can be written as ( - )=c / (a^2+b^2 ) . The solution is =2 n + , where tan =b / a, =c /