# Recent content by cd246

1. ### Substitution with integration

i finally found my error. I understand the basics(for the most part) of integration. It is the substitution and the more sophisticated equations that get me.
2. ### Substitution with integration

I cannot believe this, same problem but it is /int 4_0. I'm sorry i missed that. To answer the question of what i am doing, first I have to figure out if this is something i can use the fund. rules of integrals or something i have to (or is preferred) substitute the function. For this one, i...
3. ### Substitution with integration

I did this: u^(1/2)/(1/2). 2u^(1/2) 2(2t+4)^(1/2) (4t+8)^1/2 (12t)^(1/2) 2(3)^(1/2) I believe I am further off than the first time.
4. ### Substitution with integration

Homework Statement /int (2t+4)^-1/2 dt. the answer is 2(sqrt3)-2 Homework Equations The Attempt at a Solution u^-1/2*(1/2)du (-1/2)(u^1/2) (-1/4)(2t+4)^1/2 (-1/4)(sqrt 12)= (-1/4)(4(sqrt 3)/1)=sqrt 3 (sqrt 3)-1/2 2(sqrt 3)-1
5. ### Definite integration 2 & 3

I found what i did wrong now. thanx
6. ### Definite integration 2 & 3

Homework Statement 2. /int 1_0 (5u^7+pi^2) dx the answer is (5/8)+pi^2 3./int 4_0 (x^(1/2))(x+1) the answer is 272/15. Homework Equations The Attempt at a Solution For 2. I already have the 5/8, my question do I integrate the pi^2? I tried integrating that with no success. For...
7. ### Definite integration

ok i got it now. thanx
8. ### Definite integration

that was pretty much it. did u put x^3 on top? or did you left the x^3 on the bottom? Because i believe that was my problem on this one.
9. ### Definite integration

My apologies, it is 2_1 not 9_0
10. ### Definite integration

Homework Statement integration 9_0 c/x^3 dx. the answer is (3/8)c. Homework Equations just distrib. then plug in the #'s The Attempt at a Solution =cx^-3 = (cx^-2)/-2=c/-2x^2 I know it has something to do with distribution.
11. ### Reverse diferentiation problem

Now I know what I did wrong now, I just put x^-4 on top instead of subtracting the lower from the upper which I should have done. Thanks glenn
12. ### Reverse diferentiation problem

Homework Statement (x^2+3x-1)/x^4 the answer is,(-x^-1)-(3/2)(x^-2)+(1/3)(x^-3)+C Homework Equations Just reverse diferentiation The Attempt at a Solution =x^2+3x-1+x^-4 =(x^3)/(3)+(3x^2)/(2)-x+(1/3)(x^-3+C) (1/3)(x^3)+(3/2)(x^2)-x+(1/3)(x^-3)+C I know i got the answer but somehow it is...
13. ### L'hopital's rule

I now get the infin. multiplication part now. also, f'(x)=ln(x) g'(x)=x^5 was meant to be: f'(x)=ln(x) ----------- g'(x)=x^5 Thanks
14. ### L'hopital's rule

For 1. I would have to apply l'hopital's again because it is still 0/0. So, it would be(2-2cos(2x))/(4xcos2x+2sin2x). It is still 0/0 so i have to derive one more time. It would be 4sin2x/4xcos2x+4cos2x. Apply the 0 and got 0/4 = 0. Did I do this right now? 2. a. The limit of ln(x) is -infin...
15. ### L'hopital's rule

I would like to know if I did these the correct way. Homework Statement 1.lim x->0 (1/sin 2x)-1/2x. the answer is 0. 2.lim x->0 (x^-5*ln x). The answer is -infinity. Homework Equations 1.I used L'Hopitals theorem 2.I derived them, than L'hopitals. The Attempt at a Solution 1.I...