有關 amath ce 02 年的.....

putx=sinθ,dx=cosθdθ
when x=1/2,θ=@/6 (@=pie)
x=0,θ=0


1/2
∫ (1 - x^2)^ (-1/2) dx
0

= @/6
∫ (1-sin^2 θ)^ (-1/2) cosθdθ
0
= 1/2
∫ (cosθ/cosθ)dθ
0
= @/6
∫ dθ
0

= @/6
[θ]
0

=@/6


good

it is out c la bo~