Question

calculate an integral

Answer 1

try and substitute 9+x^2 as u

Answer 2

is there any other method, not u-sub one?

Answer 3

u can put x as 3 sin t,but it might complicate things more than u=9+x^2 substitution..

Answer 4

i was trying to use that method, but it's really easy to get mess of...

Answer 5

would you mind show me the step of using u-sub? i am not sure about my process is correct

Answer 6

i want to check ur step with mine

Answer 7

lengthy,will take some time,i'll try...

Answer 8

ok.thx

Answer 9

u can draw the whole step, i think it's easier than type

Answer 10

u = 9+x^2
du = 2x dx

did u get till here ??
x^2 = u-9