In ∫ 2x(x^(2)+3)dx, if we let u=x^(2)+3,then
1.the integral form is u^(n)du and du=2x
2.the integral form u^(n)du cannot be used because n=1
3.the integral form is u^(n)du and du=2dx
4.the integral form is u^(n)du and du=2xdx

Question

In ∫ 2x(x^(2)+3)dx, if we let u=x^(2)+3,then
1.the integral form  is u^(n)du  and du=2x
2.the integral form  u^(n)du cannot be used because n=1 
3.the integral form  is u^(n)du and du=2dx 
4.the integral form  is u^(n)du and du=2xdx

anonymous · Answer

$$here\int\limits2x(x ^{2}+3)dx_{}^{}$$
for simplification we will take  
(x^2+3)=u
by diff. both side wrt x we get 
2x+0=du/dx
so du = 2xdx & integral form is udu.
i think u r missing sum thing in the question that it must be 
integration of   2x(x^(2)+3)^n.dx
is not it........