functions !!!

Is the function F(x) = x^3+C ; where C belongs to positive real numbers including 0 ; always strictly increasing at (0,0) ??
please explain !!

7 Answers

1
Philip Calvert ·

a function is increasing or decreasing in a interval

asking about it "at (0,0)" or any point is meaning less

btw that function is strictly increasing in (-∞,∞)

1
Avinava Datta ·

ok .. but what can be said about the nature of the function about the origin ??

4
UTTARA ·

If it is strictly increasing in (-∞,∞) then it is also increasing at the origin

1
Ankur Jay ·

Double differentiate the function and find f'(x). Equate f'(x) to 0, and we get x=0.

Hence at (0,0) the slope is 0.

In the intervals (-∞,0) and (0,∞) we find that the function is increasing. But at (0,0) it is neither increasing nor deceasing.

The concept of functions tells us that "For a function to be strictly increasing, every real number C belonging to the interval (A,B) , f'(C) should be greater than 0."

But we find that at x=0, f'(x) = 0.

So this function is not strictly increasing.

And besides, the concepts also tell us that "If the sign of f'(x) does not change as it passes through C, then C is a point of inflection ."

Hence, origin is a point of inflection.

This function is increasing only.

1
Arka Halder ·

agree with philip.
the function has a value C at (0,0).
the question of increasing or decreasing arises only in an interval.

1
Ankur Jay ·

Yep... agree... the question of increasing or decreasing arises only in an interval.

1
Avinava Datta ·

thnx frndz allof u !!!

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