Question

Evaluate:

anti-derivative x dx/sqrt(x^2+1)

Answer 1

I get
u= x^2+1
du = 1 dx

Answer 2

put x^2 +1 =t
diff w.r.t. x , we get
2x dx= dt

Answer 3

i.e. x dx= dt/2

Answer 4

u could even substitute sqrt(x^2+1)=t than can work too

Answer 5

tan(t) = x ; dt sec^2 = dx; t = tan^-1(x)..lets start :)

x dx tan(t) sec^2(t) dt
-------- --> ---------------
(x^2 +1) tan^2 +1 <-- this is eqaul to sec^2

Answer 6

[S] tan(t) dt

Answer 7

(x^2 + 1)^1/2 + c

Answer 8

yeah, it helps if you read the sqrt part ;).....

Answer 9

...if you ever need to do the one I was working on....lol

Answer 10

when I re did it with the approriate sqrt.... I got\[\int\limits_{}\frac{\tan(t)\sec^2(t)}{\sec(t)}dt \rightarrow \int\limits_{} \sec(t)\tan(t)dt \rightarrow \sec(t)\]

Answer 11

\[\sec(t) = \sqrt{x^2+1}\]

Answer 12

+C lol

Answer 13

I started a new problem

Answer 14

yay!! .... I was just trying to wrap this one up in me brain :)