`(a) 4 sin^(2) theta=3 " " (b) cos^(2) theta = (1)/(4)`
`(c ) cot^(2) theta =3 " " (d ) sin^(2) theta = (1)/(4)`

Answer

`(a)n pipm(pi)/(3)" "(b)n pi+-(pi)/(3)" "(c)n pipm(pi)/(6)" "(d)n pi+(pi)/(6)`