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  1. H

    How to know original value after percentage?

    Then I stongly recommend you hire a bookkeeper to do the arithmetic for you!
  2. H

    t & w q10

    Samojit, this is what they mean: Let "w" be the amount of work does in one day and let "m" be the amount of work a man does in one day. "It takes 6 days for 3 women and 2 men working together to complete a work." 3(6)w+ 2(6)m= 18w+ 12m= 1 work. "3 men would do the same work 5 days sooner than...
  3. H

    Base 12 math prodigy needed

    Really doesn't matter what you think- there's reality! (It occurs to me that your post might be interpreted "I never thought I was a prodigy and then found out I was"!)
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    Numerical integration - polynomial order confusion

    That makes no sense. Numbers have averages, not points! Of course, it is true that there exist a unique line through two given points. Is that what you mean? That is a basic property, in fact, a postulate, of Euclidean Geometry.
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    Can anyone Plz sove me these questions

    Do you understand what these questions mean? The first asks you to use the "bisection method" to numerically solve the equation x^3- 3= 0. Do you understand what the "bisection method" is? I notice that if x= 0, x^3- 3= 0- 3= -3 which is less than 0 and that if x= 2, x^3- 3= 8- 3= 5 which is...
  6. H

    Ayudaaaaaa

    The "characteristic equation" for this differential equation is r^2- 5r+ 6= (r 3)(r- 2)= 0 so the "characteristic numbers" are 2 and 3. That means that the general solution to the "associated homogeneous equation, y''- 5y'+ 6y= 0, is Ae^{2x}+ Be^{3x}. Normally, with the "non-homogeneous" part...
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    How to convert this system of non-linear diff equations into vector form

    First, you can't "convert a non-linear differential equations into vector form" because vector spaces are necessarily linear. The best you can do is approximate the non-linear differential equations by linear equations then convert them to vector form. For these equations the best...
  8. H

    Help with integrating the volume of cone while keeping the cone the right way up.

    I don't see anywhere in what you have posted that gives the actual original cone!
  9. H

    Need help on piecewise function

    For x< 5, \frac{x^2- 25}{x- 5}= \frac{(x- 5)(x+ 5)}{x- 5}= x+ 5 so the limit, as x goes to 5 from below is 5+ 5= 10. The limit, as x goes to 5 from below, of f is 10d+ c. Cosine is always between -1 and 1 and x- 5 goes to 0 as x goes to 0 so the limit, as x goes to 5 from above, of this function...
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    Numerical integration - polynomial order confusion

    I presume you know the basics of integration: \int a dx= ax+ c \int ax dx= \frac{a}{2}x^2+ c \int ax^2 dx= \frac{a}{3}x^3+ c and in general \int ax^n dx= \frac{a}{n+1}x^{n+1}+ c. That is, the integral of a polynomial of degree n is a polynomial of degree n+ 1. (Notice that I am using the word...
  11. H

    Equation tangent to a line

    Do you understand what a "tangent" is? The tangent to a graph at a point is a straight line that passes through that point and has the same slope (derivative) there. Do you understand what "y= 3" means? Since y is always 3 any (x, y) point is (x, 3). The graph is a horizontal straight line...
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    Polynomial Division which leaves remainders

    First, since dividing P by quadratic polynomials leaves first degree remainders, P itself must be cubic: P(x)= ax^3+ bx^2+ cx+ d \frac{ax^3+ bx^2+ cx+ d}{x^2- 2x- 8}= Q(x)- x+ 5 so [
  13. H

    Base 12 math prodigy needed

    I once thought I was a prodigy but reality soon slapped me in the face!
  14. H

    How would I go about finding the weight of something with the square cube law?

    If you do not assume that then it is impossible to do this problem.
  15. H

    math question

    There were initially 670 grams. Since it decays by 27.3% per minute, there is left (100- 27.3)%= 72.7% per minute. That means that after one minute there is 72.7% of 670= 0.727(670)= 487.09 grams left. And after the second minute there is 72.7% of 487.09= 0.727(487.09)= 354.11443 grams left...
  16. H

    Math Problem

    Yes, and subtracting the second equation from the first eliminates a: a- b- (a- 2b)= (a- a)- (b- 2b)= b= 4-(-6)= 4+ 6= 10 and a- b= a- 10= 4 so a= 4+ 10= 14. There are 14 children in bus A and 10 children in bus B. Check: Transfering two children from bus A to bus B leaves 14- 2= 12 children...
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    √(5x-4)=x-2 extraneous solution

    While there are 2 values of x such that x^2= a^2, x= a and x= -a, \sqrt{a^2} is specifically defined as the positive root, |a|.
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    Laplace transformations

    Do you know that the Laplace Transform of f(x) is defined as F(t)= \int_0^\infty f(s)e^{-st}ds? With this f that is \int_0^2 -t e^{-st}dt. To integrate that, use "integration by parts" with u= -t and dv= e^{-st}. du= -dt v= -(1/s)e^{-st} (t/s)e^{-st}|_0^2+ (1/s)\int_0^2 e^{-st}dy...
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    Can't understand a simplification

    You have 14(2x+ 4)^6(3x- 2)^5+ 15(2x+ 4)^7(3x- 2)^4. Do you see that there is a "(2x+ 4)" in both terms? One is to the 6th power and the other is to the 7th power. (2x+ 4)^7= (2x+ 4)^6(2x+ 4) so there is (2x+ 4)^6 in both terms and we can factor that out, leaving 2x+ 4 to the first power in...
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    Base 12 math prodigy needed

    How about someone who is no prodigy buit knows what "base 12" is? In any case what is this "super cool task"?
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