やっと数合った
1.√3/12
2.189
3.(a.b)=(3,1)tanC=√2-1
4.境界はz=√x,z=√x-1/4,z=x^2/1ー2x
5,(1)2/5(1-(-1/4)^n)
 (2)1/5-1/5(-1/4)^n+1/3(3/4)^n
6(1)r=cosθ/1+sin^2θ
 (2)α=-1,T=1/3(3)β=-1,U=-π/4(4)2/3