Question:

Differentiate the functions with respect to x.
\(sin(x^2+5)\)

Updated On: Sep 29, 2023
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Solution and Explanation

Let f(x) = sin (x2+5), u(x) = x2+5, and v(t) = sin t
Then, (vou)x = v(u(x)) = v(x2+5) = tan(x2+5) = f(x)
Thus, f is a composite of two functions.

Put t = u(x) = x2+5
Then we obtain 
\(\frac {dv}{dt}\) = \(\frac {d}{dt}\)(sin t) = cos t = cos (x2+5)
\(\frac {dt}{dx}\) = \(\frac {d}{dt}\)(x2+5) = \(\frac {d}{dt}\)(x2) + \(\frac {d}{dt}\)(5) = 2x+0 = 2x
Therefore by chain rule, \(\frac {df}{dx}\) = \(\frac {dv}{dt}\) . \(\frac {dt}{dx}\) = cos (x2+5) . 2x = 2x cos(x2+5)

Alternate method:
\(\frac {d}{dx}\)[sin (x2+5)] = cos (x2+5) . \(\frac {d}{dx}\)(x2+5)
=cos (x2+5) . [\(\frac {d}{dx}\)(x2) + \(\frac {d}{dx}\)(5)]
=cos (x2+5) . [2x + 0]
=2x cos (x2+5)

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Derivatives

Derivatives are defined as a function's changing rate of change with relation to an independent variable. When there is a changing quantity and the rate of change is not constant, the derivative is utilised. The derivative is used to calculate the sensitivity of one variable (the dependent variable) to another one (independent variable). Derivatives relate to the instant rate of change of one quantity with relation to another. It is beneficial to explore the nature of a quantity on a moment-to-moment basis.

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