Get Expert Help with Basic Integrals | General Formula and Practice Exercises

[stud]

I need help please with a basic integral.

http://i40.tinypic.com/a589qp.gif

These integrals is immediate?
What the general formula?

And here, exercises 1 & 4:
http://i43.tinypic.com/zksmck.gif

Thanks.

 

[Curious3141]

I need help please with a basic integral.

http://i40.tinypic.com/a589qp.gif

These integrals is immediate?
What the general formula?

And here, exercises 1 & 4:
http://i43.tinypic.com/zksmck.gif

Thanks.

What have you tried?

You have to show work before any help is given. From the FAQ:

1) Did you show your work? Homework helpers will not assist with any questions until you've shown your own effort on the problem. Remember, we help with homework, we don't do your homework. We already passed those classes, it's your turn to do so.

 

[stud]

hey curious,
can how show my effort to solve this exercise?

i am not know to solve this integral, because i ask help please.

 

[Mentallic]

hey curious,
can how show my effort to solve this exercise?

You can show what you've tried by typing it out step by step, for example:

x²-2=0
x²=2
x= +/- sqrt(2)

or better yet, use Latex!

$$x^2-2=0$$
$$x^2=2$$
$$x=\pm\sqrt{2}$$

These can be written as follows (taking out the spaces in the tex tags)

[ tex]x^2-2=0[ /tex]
[ tex]x^2=2[ /tex]
[ tex]x=\pm\sqrt{2}[ /tex]

For integrals, use

$$\int{\frac{x}{x^2+1}}$$

[ tex]\int{\frac{x}{x^2+1}}[ /tex]

If you ever see latex being used and want to know how to type it yourself, you can quote that message and in the quote it will show you the text required.

i am not know to solve this integral, because i ask help please.

For the first two, think about using this technique:

$$\frac{a}{a+b}=\frac{a+b-b}{a+b}=1-\frac{b}{a+b}$$

 

[Curious3141]

For the first two, think about using this technique:

$$\frac{a}{a+b}=\frac{a+b-b}{a+b}=1-\frac{b}{a+b}$$

That was the *exact* hint I was thinking about providing before I decided to wait for TS' reply first and went offline. *Exact*, word for word, same symbols and everything. You ARE a mindreader, Mentalist, oops, Mentallic.

Stud: This is a very good hint. For the first integral, you get an almost-immediate answer, without needing any substitution. The second integral, you can get an almost-immediate answer for it if you recognise a particular form (hint: derivative of $\arctan{x}$). If not, you can try a $x = \tan\theta$ substitution on the second term after applying this trick.

Mentallist, I or someone else can hint you along with the rest as well, but you HAVE to show some work here first. Deal?