Given:
#y=arcsin(csc(x^3))#
#arcsin(csc(x^3))=sin^-1(csc(x^3))#
Let #t=csc(x^3)#
#y=sin^-1t#
#(dy)/dt=1/sqrt(1-t^2)=1/sqrt(1-(csc(x^3))^2#
#(dy)/dx=(dy)/(dt)(dt)/dx#
#t=csc(x^3)#
Let #u=x^3#
#t=cscu#
#(dt)/(du)=cscucotu=csc(x^3)cot(x^3)#
#(dt)/dx=(dt)/(du)(du)/(dx)#
#(du)/(dx)=3x^2#
#(dt)/dx=(csc(x^3)cot(x^3))(3x^2)=3x^2csc(x^3)cot(x^3)#
#(dy)/dx=1/sqrt(1-(csc(x^3))^2)(3x^2csc(x^3)cot(x^3))#
#(dy)/dx=(3x^2csc(x^3)cot(x^3))/sqrt(1-(csc(x^3))^2)#