cosec(6a+pi/8)=sec(2a-pi/8)

=>sin(6a+pi/8)=cos(2a-pi/8)

=>sin(6a+pi/8)=sin(pi/2-2a+pi/8)

=>6a+pi/8=5pi/8-2a

=>8a=4pi/8

=>a=pi/4=the principal value

it becomes lengthy for integral values.the answer is

a=1/3*n*pi+pi/16 where n belongs to integral values.please comment!!