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Show that function f(x) =3x+10, x ≠ 0 is decreasing.

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Question

Show that function f(x) =`3/"x" + 10`, x ≠ 0 is decreasing.

Sum
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Solution

f(x) = `3/"x" + 10`

For function to be decreasing, f '(x) < 0

Then f '(x) = `(- 3)/"x"^2 < 0`    ....[∵ x ≠  0, - x2 < 0]

Negative sign indicates that it always decreases as x2 never becomes negative.

Thus, f(x) is a decreasing function for x ≠ 0.

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Chapter 4: Applications of Derivatives - Miscellaneous Exercise 4 [Page 114]

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Balbharati Mathematics and Statistics 1 (Commerce) [English] Standard 12 Maharashtra State Board
Chapter 4 Applications of Derivatives
Miscellaneous Exercise 4 | Q 4.4 | Page 114

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