How to find the first 3 roots of sin(x)+0.5=0 bigger than zero? (Multiple roots)

Without using fzero function and without plotting the sin(x)+0.5 to find where the plot coincides with the x-axis, is there another way to obtain the first 3 roots of sin(x)+0.5=0?

Thanks Efe

Answer 1

[Mischa Kim]

Efe, that looks like a trick question... sin(x)+5 cannot be equal to zero, since sin(x) is between -1 and +1.

[efe]

Sorry for punctuation it should be sin(x)+.5=0.

[Mischa Kim]

You can use any root-finding algorithm (Bisection, Newton-Raphson, etc.) to get the first root (e.g. in [pi,3*pi/2]) and then use symmetry and periodicity of the sine to get as many of the other roots as you need to.