Solving an Unwieldy Differential Equation












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I am at the end of a very long math problem and am left with this equation.



I know. It's monstrous.



This equation is equal to $frac{dtheta}{dt}$, and I would like to solve it as a differential equation. The only way I've found that might work is the separation of variables strategy:
$$frac{dtheta}{dt}=f(t)g(theta)$$
$$frac{1}{g(theta)}dtheta=f(t)dt$$
$$intfrac{1}{g(theta)}dtheta=int f(t)dt$$
$$G(theta)+c_1=F(t)+c_2$$
$$G(theta)-F(t)=C$$
The issue is that teasing apart the variables in this equation seems like it will take a very, very long time, not to mention taking the integral of what is left. It feels like this is the wrong way to do it.



So, my question is this: how do I solve this differential equation?



Thank you for all the help you can give.










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    0












    $begingroup$


    I am at the end of a very long math problem and am left with this equation.



    I know. It's monstrous.



    This equation is equal to $frac{dtheta}{dt}$, and I would like to solve it as a differential equation. The only way I've found that might work is the separation of variables strategy:
    $$frac{dtheta}{dt}=f(t)g(theta)$$
    $$frac{1}{g(theta)}dtheta=f(t)dt$$
    $$intfrac{1}{g(theta)}dtheta=int f(t)dt$$
    $$G(theta)+c_1=F(t)+c_2$$
    $$G(theta)-F(t)=C$$
    The issue is that teasing apart the variables in this equation seems like it will take a very, very long time, not to mention taking the integral of what is left. It feels like this is the wrong way to do it.



    So, my question is this: how do I solve this differential equation?



    Thank you for all the help you can give.










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$


      I am at the end of a very long math problem and am left with this equation.



      I know. It's monstrous.



      This equation is equal to $frac{dtheta}{dt}$, and I would like to solve it as a differential equation. The only way I've found that might work is the separation of variables strategy:
      $$frac{dtheta}{dt}=f(t)g(theta)$$
      $$frac{1}{g(theta)}dtheta=f(t)dt$$
      $$intfrac{1}{g(theta)}dtheta=int f(t)dt$$
      $$G(theta)+c_1=F(t)+c_2$$
      $$G(theta)-F(t)=C$$
      The issue is that teasing apart the variables in this equation seems like it will take a very, very long time, not to mention taking the integral of what is left. It feels like this is the wrong way to do it.



      So, my question is this: how do I solve this differential equation?



      Thank you for all the help you can give.










      share|cite|improve this question









      $endgroup$




      I am at the end of a very long math problem and am left with this equation.



      I know. It's monstrous.



      This equation is equal to $frac{dtheta}{dt}$, and I would like to solve it as a differential equation. The only way I've found that might work is the separation of variables strategy:
      $$frac{dtheta}{dt}=f(t)g(theta)$$
      $$frac{1}{g(theta)}dtheta=f(t)dt$$
      $$intfrac{1}{g(theta)}dtheta=int f(t)dt$$
      $$G(theta)+c_1=F(t)+c_2$$
      $$G(theta)-F(t)=C$$
      The issue is that teasing apart the variables in this equation seems like it will take a very, very long time, not to mention taking the integral of what is left. It feels like this is the wrong way to do it.



      So, my question is this: how do I solve this differential equation?



      Thank you for all the help you can give.







      calculus differential-equations






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      asked Dec 4 '18 at 16:27









      Levi BuckwalterLevi Buckwalter

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          $begingroup$

          HINT



          For starters, simplify the denominator noting that
          $$
          l^2 sin^2 theta + l^2 cos^2 theta = l^2,
          $$

          and cancel one of the $l$ factor with the numerator. Finally, I would try to simplify the massive trig function on the RHS using various trig summation of sines and cosines to compact it down.






          share|cite|improve this answer









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            1 Answer
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            1 Answer
            1






            active

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            active

            oldest

            votes









            0












            $begingroup$

            HINT



            For starters, simplify the denominator noting that
            $$
            l^2 sin^2 theta + l^2 cos^2 theta = l^2,
            $$

            and cancel one of the $l$ factor with the numerator. Finally, I would try to simplify the massive trig function on the RHS using various trig summation of sines and cosines to compact it down.






            share|cite|improve this answer









            $endgroup$


















              0












              $begingroup$

              HINT



              For starters, simplify the denominator noting that
              $$
              l^2 sin^2 theta + l^2 cos^2 theta = l^2,
              $$

              and cancel one of the $l$ factor with the numerator. Finally, I would try to simplify the massive trig function on the RHS using various trig summation of sines and cosines to compact it down.






              share|cite|improve this answer









              $endgroup$
















                0












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                0





                $begingroup$

                HINT



                For starters, simplify the denominator noting that
                $$
                l^2 sin^2 theta + l^2 cos^2 theta = l^2,
                $$

                and cancel one of the $l$ factor with the numerator. Finally, I would try to simplify the massive trig function on the RHS using various trig summation of sines and cosines to compact it down.






                share|cite|improve this answer









                $endgroup$



                HINT



                For starters, simplify the denominator noting that
                $$
                l^2 sin^2 theta + l^2 cos^2 theta = l^2,
                $$

                and cancel one of the $l$ factor with the numerator. Finally, I would try to simplify the massive trig function on the RHS using various trig summation of sines and cosines to compact it down.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Dec 4 '18 at 16:35









                gt6989bgt6989b

                33.3k22452




                33.3k22452






























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