If gradient is pi/6 then gradient of tangent is pi/6 .
You need corrosponding x and y values so sub t=pi/2 into your x and y equations.
x=(3/2)pi-2 y=pi²/4 m=gradient=pi/6
plug all xym into =>y-y1=m(x-x1)
y-(pi²/4)=pi/6[x-(1.5pi-2)]
simiplify this for your answer.