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Types of DEs
Manipulation
Examples
  • Example 1
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  • Example 3
  • Example 4
  • Example 5
  • Example

    Consider for example

    y + x = -4.

    This function can be differentiated normally by using algebra to change this equation to an explicit function:

    f(x) = y = −x - 4;

    such differentiation would result in a value of −1. Equally, one can use implicit differentiation;

    dy/dx + dx/dx = 0 = dy/dx + 1; dy/dx = -1.

    An example of an implicit function, for which implicit differentiation might be easier than attempting to use explicit differentiation, is

    x4 + 2y2 = 8.

    In order to differentiate this explicitly , one would have to obtain (via algebra)

    f(x) = y = \pm\sqrt{\frac{8 - x^4}{2}},

    and then differentiate this function. This creates two derivatives, one for y > 0 and another for y < 0. Implicit differentiation avoids this.

    One might find it substantially easier to implicitly differentiate the implicit function;

    4x3 + 4y(dy/dx) = 0;

    thus,

    dy/dx = −4x3 / 4y = −x3 / y.




    Solving linear equations