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Find the instantaneous rate of change of k(x) = x at x = 9.

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Answer:


k^(\prime)(9) = 1.

Explanation:

The expression
k(x) = x is equivalent to
k(x) = x^(1).

Apply the power rule of differentiation. For any constant
a:


\displaystyle (d)/(dx)[x^(a)] = a\, x^(a-1).

In
k(x) = x^(1),
a = 1. Thus:


\begin{aligned}k^(\prime)(x) &= (d)/(dx)[x^(1)] \\ &= 1\, x^(1 - 1) \\ &= x^(0) \\ &= 1 && \text{given that $x \\e 0$}\end{aligned}.

In other words, the instantaneous rate of change of
k(x) (with respect to
x) is constantly
1 at all
x \\e 0.

Therefore, for
x = 9, instantaneous rate of change of
k(x) (with respect to
x) would be
1.

User Tathagata
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