`1, 0^o < alpha < 90^o => cosalpha >0`

`sin^2 alpha + cos^2alpha =1`

`=> (1/2)^2 + cos^2alpha =1`

`=>cos^2 alpha = 3/4`

`=>cos alpha = sqrt3/2`

`tan alpha = (sin alpha)/(cos alpha) = 1/2 : sqrt3/2 = sqrt3/3`

`cot alpha = 1 : tan alpha = 1: sqrt3/3 = sqrt3`

`2, sin^2 alpha + cos^2alpha =1`

`=> (3/4)^2 + sin^2alpha =1`

`=>  sin^2alpha =7/16`

`=>sin alpha = sqrt7/4`

`tan alpha = (sin alpha)/(cos alpha) =  sqrt7/4 : 3/4 = sqrt7/3`

`cot alpha = 1 : tan alpha = 1: sqrt7/3 = (3sqrt7)/7`