
Math
Differential equations Solutions
IR denotes the reaction of the body to some stimulus of strength x the sensitivity S is defined to
be the rate of change of the reaction with respect to x. A particular example is that when the
brightness x of a light source is increased, the eye reacts by decreasing the area R (square
millimeters) of the pupil.
A formula used to model the dependence of Ron x is: R(x) = (40 + 24 x^(2/5))/(1+4
*2/5). The sensitivity can be found by the derivative 5 - dR/dx = R'(x). This derivative can be
found by
NWU
o applying the Quotient Rule on the overall problem and the Power Rule in individual derivatives, such as R'(X)
=[(1 +4x^(2/53"(24 (2/5***(-3/5) - (40 + 24 x^(2/5)44 1275) 13/5) / (1+ 4 x 2/5)) ^2, and
then simplifying
+
o dividing the derivative of the denominator by the derivative of the numerator with the use of the Power Rule,
such as R b) = (4 (2/5) > ^(-3/5)] / [24 (2/5) X^(-3/5). and then simplifying
o dividing the derivative of the numerator by the derivative of the denominator with the use of the Power Rule,
such as Rºbx) = [24 (2/5) x^(-3/5)] / [4 (2/5) x^(-3/5), and then simplifying
o "cancelling the x^(2/5) in the original function, and then reducing R(x) = (40 +24)/(1 + 4) to 64/5, which is a
constant having derivative R'(x) = 0