2081 10

Mathematics I20815 marksNumerical: differential equation verificationIntroduction to first order equations Separable equations

Show that every member of the family of function y = frac1 + cet1 - cet is a solution of the differential equation y' = frac12(y2 - 1).

Show that every member of the family of function $y = \frac{1 + ce^t}{1 - ce^t}$ is a solution of the differential equation $y' = \frac{1}{2}(y^2 - 1)$. [5]

  • Family of functions: $y = \dfrac{1 + ce^t}{1 - ce^t}$ - Differential equation: $y' = \dfrac{1}{2}(y^2 - 1)$ Using the quotient rule with $u = 1 + ce^t$, $v = 1 - ce^t$: $$u' = ce^t, \qquad v' = -ce^t$$ $$y' = \frac{u'v - uv'}{v^2} = \frac{ce^t(1 - ce^t) - (1 + ce^t)(-ce^t)}{(1 - ce^t)^2}$$ Simp...
Up nextIf f(x,y) = 2x3 + x2y2 - y4, find fx(1,-2), fy(1,-1) and fyx(1,-1).