Find all solutions to the equation cos3zpi0Solutioncos 3z p

Find all solutions to the equation cos(3z+pi)=0

Solution

cos (3z + pi) = 0    using a trig identity, we have :

cos(3z)cos(pi) - sin(pi)sin(3z) = 0

-cos(3z) = 0

cos(3z) = 0

cos(z) = 0   at   pi/2 + n*pi

So

3z = pi/2 + n*pi       divide both sides by 3

z = pi/6 + n* (pi/3)   where n is any integer