Should u-substitution be used? *HUGE MISTAKE*

Пікірлер: 41

  • @nickulman9739
    @nickulman9739 Жыл бұрын

    If you rewrite numerator as x^4+1-1. Then break up into to fractions (x^4 -1)/(x^2+1) +1/(x^2+1). Second fraction is simply arctan(x) when integrated. First fraction factors as diff of squares into (x^2-1)*(x^2+1) /(x^2+1)=x^2-1. When integrated that gets you (x^3)/3 - x. Therefore the final answer is: (x^3)/3 - x + arctan(x)

  • @ClydeSimpson-vv3hj
    @ClydeSimpson-vv3hj Жыл бұрын

    Using long division you obtain: x^2 - 1 - 1/x^2 + 1. You then integrate, remember that 1/x^2 + 1 is arctan. 1/3x^3 - x - arctan(x) +C

  • @moeberry8226

    @moeberry8226

    Жыл бұрын

    It’s +arctan(x) not -arctan(x).

  • @amanielmeharena3885

    @amanielmeharena3885

    Жыл бұрын

    Can you explain why 1/x²+1 is arctan(x)?

  • @moeberry8226

    @moeberry8226

    Жыл бұрын

    @@amanielmeharena3885 1/(x^2+1) is not arctan(x), THE INTEGRAL OF 1/(x^2+1) is arctan(x). Because if you differentiate arctan(x) you obtain 1/(x^2+1).

  • @elimhorn3308

    @elimhorn3308

    Жыл бұрын

    @@amanielmeharena3885 it’s the integral of arctan x, and that’s just the formula.

  • @e2vbeast549
    @e2vbeast549 Жыл бұрын

    Just add and subtract 1 in the numerator then the question will be like x^4 +1 -1/x^2+1 then (x^2)2-(1)^2 +1/x^2+1 now (x^2+1)( x^2-1 ) /x^2+1 + int 1/x^2+1dx so by eliminating x^2+1 we get int x^2-1dx + int 1/x^2+1 dx so it will be 1/3 x^3 + tan-1x + c as int of tan-1x =1/1+x^2

  • @user-in1gd4ub7j
    @user-in1gd4ub7j Жыл бұрын

    Add and subtract 1 on the numerator and break into 2 fractions ,use the difference of squares on the x^4 -1 and so on

  • @mikedavis7636
    @mikedavis7636 Жыл бұрын

    Do a trig sub. Set X = tan ø in the numerator it's pretty big tan ⁴ ø but in the denominator it becomes tan squared plus one, this turns to sec ²ø and that cancels out because of the derivative of tan in the numerator. In the end, you split into 2 tan²ø, use the sec identity, one u sub later you get 1/3x³ - X + tan-¹ X + c. Had a feeling there would be an arctan in the answer because thr derivative x² +1 is in the denominator.

  • @bonganindlovu5115
    @bonganindlovu5115 Жыл бұрын

    Long division also

  • @AJ-er9my
    @AJ-er9my Жыл бұрын

    looks like one of those trig sub integrals

  • @AJ-er9my

    @AJ-er9my

    Жыл бұрын

    for tangent

  • @meteoktem
    @meteoktem Жыл бұрын

    X^2+1=(square root x^2+1)^2 then I would use trigonometric subs

  • @kianmath71
    @kianmath71 Жыл бұрын

    Easy integral, use x = tanthetha, and it becomes integral of tan^4theta and aplitting it up we get an answer of x^3/3-x+arctanx

  • @wakeupthewublins69
    @wakeupthewublins69 Жыл бұрын

    Use the method where you multiply by one.

  • @ericterry4544
    @ericterry4544 Жыл бұрын

    us a trig substitution?

  • @sagarmajumder7806
    @sagarmajumder7806 Жыл бұрын

    Use binomial theorem to integrate that 😎

  • @adhamd397
    @adhamd397 Жыл бұрын

    Just use eucliden divison you will x^2-1+1/x^2+1 dx which by distribution of dx you ll get x^3/3-x +arc tan (x) + cste

  • @hetalkatharotiya5501
    @hetalkatharotiya5501 Жыл бұрын

    just do + and - 1 in numerator

  • @kryvi9415
    @kryvi9415 Жыл бұрын

    nice

  • @boraned
    @boraned Жыл бұрын

    But there was no "dx" at the beginning. So you can't do it. Am I right? I dunno man, im still in 11th grade.

  • @forcetamil6990
    @forcetamil6990 Жыл бұрын

    Plz write dx in question

  • @mathscribbles

    @mathscribbles

    Жыл бұрын

    Yes, that was a typo - sorry for not being perfect ☺️

  • @elimhorn3308

    @elimhorn3308

    Жыл бұрын

    @@mathscribbles you don’t have to be so passive aggressive, but you should definitely put an equal sign between du/2x and dx.

  • @mathscribbles

    @mathscribbles

    Жыл бұрын

    @@elimhorn3308 was not trying to be passive aggressive at all! I acknowledged the typo and that I'm not perfect. 🤗

  • @dwrchschr
    @dwrchschr Жыл бұрын

    Add and subtract x² in the numerator, so you can have x²-x²/(x²+1) Than again getting x²-1+1/(x²+1) And this one is easy to integrate

  • @colinjava8447

    @colinjava8447

    Жыл бұрын

    Yeah I got the same thing, I think the last bit is tan^-1(x) when integrated

  • @dwrchschr

    @dwrchschr

    Жыл бұрын

    @@colinjava8447 it is!

  • @Lil_shrimp4

    @Lil_shrimp4

    Жыл бұрын

    Yeah add and subtract one to the top factorise cancel and split the integral

  • @rithwikrajasekhara1524
    @rithwikrajasekhara1524 Жыл бұрын

    3/2-1 + 1

  • @michaeldominguezjr7503
    @michaeldominguezjr7503 Жыл бұрын

    What kind of computer are y you using for that sir? I’m a physics student looking to get me one and shopping around right now.

  • @mathscribbles

    @mathscribbles

    Жыл бұрын

    This is an iPad and using the Goodnotes app. Highly recommend!

  • @michaeldominguezjr7503

    @michaeldominguezjr7503

    Жыл бұрын

    @@mathscribbles thanks for the quick reply my man. I’m gonna go look now! 👍🏾

  • @Politictrolerandenthusiast
    @Politictrolerandenthusiast Жыл бұрын

    Hey, can anyone tell me what's going on here? Because i do not understand calculus yet maybe because I'm a freshman in highschool although I'm really intrigued by mathematics yet so far off from my grasp. So if anyone could explain to me in a way that I can understand then good job you would be an A star teacher

  • @amrashraf4851
    @amrashraf4851 Жыл бұрын

    Partiallllll fraction

  • @edizedomat1135

    @edizedomat1135

    Жыл бұрын

    Nope, you can not do it like that

  • @patrickfarrell6192
    @patrickfarrell6192 Жыл бұрын

    Long division😩

  • @nathaenwanta6452
    @nathaenwanta6452 Жыл бұрын

    As someone who is pursuing a degree in mathematics, the lack of dx viscerally upsets me

  • @bonganindlovu5115
    @bonganindlovu5115 Жыл бұрын

    Trig sub this one

  • @Congnhan.NailtoclabonthathcNGU
    @Congnhan.NailtoclabonthathcNGU Жыл бұрын

    U = x^2 its arctan 😂