Recent content by Mark Brewer

  1. Mark Brewer

    How can partial fractions be used to solve inverse Laplace transforms?

    Okay. Thank you, I'll reply as soon as I see my mistakes.
  2. Mark Brewer

    How can partial fractions be used to solve inverse Laplace transforms?

    sorry, I'm not sure if I can split the roots to two rationals.
  3. Mark Brewer

    How can partial fractions be used to solve inverse Laplace transforms?

    I'm not sure if splitting the roots, or can I?
  4. Mark Brewer

    How can partial fractions be used to solve inverse Laplace transforms?

    Homework Statement L-1{(2s2+3)/(s2+3s-4)2} The Attempt at a Solution I factored the denominator f(t)=(2s2+3)/((s-1)(s+4))2 now I've tried partial fractions to get (2s2+3)/((s-1)(s+4))2 = A/(s-1)2 + B(s+4)2 (2s2+3)=A(s+4)2 + B(s-1)2 by substitution, s=1 and s=-4 5=A(25) A=1/5 35=B(25)...
  5. Mark Brewer

    What is the Generating Function for Bessel Functions?

    Thank you, Greg. You can bump this post.
  6. Mark Brewer

    What is the Generating Function for Bessel Functions?

    Homework Statement Show that the Bessel functions Jn(x) (where n is an integer) have a very nice generating function, namely, G(x,t) := ∑ from -∞ to ∞ of tn Jn(x) = exp {(x/2)((t-T1/t))}, Hint. Starting from the recurrence relation Jn+1(x) + Jn-1(x) = (2n/x)Jn(x), show that G(x,t)...
  7. Mark Brewer

    Polynomial solution to Legendre's equation

    I'm not sure why the second half of my problem is in a subscript. The double checked the problem by previewing it, but I could get the text out of being in a subscript. My apologies for this.
  8. Mark Brewer

    Polynomial solution to Legendre's equation

    Homework Statement Starting from the recurrence relation, show that, when l is an integer, the polynomial solution to Legendre's equation is yl(x) = Kl ∑ from k = 0 to (l/2) of (((-1)k) / k!) (((2l - 2k)!) / (l-k)! (l - 2k)!) (xl-2k) where Kl is an arbitrary constant (depending on l) and x...
  9. Mark Brewer

    How to Solve the Differential Equation y'' + y = tan^2(x)?

    My new answer is extremely long. y = c1sinx + c2cosx + sin2x - xcosx(xsinx - 1) - lntanx + secx - cosx(sinxtanx - 2) -xsinx(cosx + 1)
  10. Mark Brewer

    How to Solve the Differential Equation y'' + y = tan^2(x)?

    Hi Ehild, My apologies for thinking I could use sec2x - 1. I thought the derivation was tanx from sec2x. I'll use sinx/cosx. Thank you again for the help.
  11. Mark Brewer

    How to Solve the Differential Equation y'' + y = tan^2(x)?

    Thank you, the secant should have been sec2x -1
  12. Mark Brewer

    Finding a Second Linearly Independent Solution Using Reduction of Order

    Homework Statement (Reduction of order) The function y1 = x-1/2cosx is one solution to the differential equation x2y" + xy' + (x2 - 1/4) = 0. Use the method of reduction of order to find another linearly independent solution. The Attempt at a Solution I divided x2 to both sides to get the...
  13. Mark Brewer

    How to Solve the Differential Equation y'' + y = tan^2(x)?

    W = 1 r = tan2x y1 = sinx y2 = cosx yh = c1sinx + c2cosx yp = -y1 ∫ ((y2)(r)/W)dx + y2 ∫ ((y1)(r)/W)dx yp = -sinx ∫ ((cosx)(tan2x)dx) + cosx ∫ ((sinx)(tan2x)dx) yp = -sinx ∫ ((cosx)(sec2x +1)dx) + cosx ∫ ((sinx)(sec2x +1)dx) There's two by parts labeled 1 (left side) and 2 (right side)...
  14. Mark Brewer

    How to Solve the Differential Equation y'' + y = tan^2(x)?

    Thank you for the reply. I retried by parts and saw that trig identities simplify the integrals, so I don't have to do by parts a second time. I apologize for not displaying my integrals. My answer is y = c1sinx + c2cos +cosx if you still want to see my work I can display it, but it's a lot...
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