∫ 1 /(1-x^2)^0.5dx = arcsinx +C
∫1/(a^2-x^2)dx = arcsinx/a+C
∫1/(1+x^2)dx = arctanx +C
∫1/(a^2+x^2)dx = 1/a arctan(x/a) +C
∫1/(a^2+x^2)^0.5dx = ln(x+(x^2+a^2)^0.5)+C
∫1/(a^2-x^2)^0.5dx = ln|x-(x^2+a^2)^0.5|+C
∫ 1/(x^2-a^2)dx = ln|x-a|/|x+a|+C
∫(a^2-x^2)^0.5dx = a^2/2*arcsinx/a+x/2*(a^2-x^2)^0.5+C