question archive Determine all of the relative extreme values of the function f (x) = 3x4 — 2x3 — 1 The relative extreme value occurs at x = 1/3 The relative extreme values occur at x = 0 and 1/3 The relative extreme values occur at x = 1/2 There are no relative extreme values
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Determine all of the relative extreme values of the function f (x) = 3x4 — 2x3 — 1
The relative extreme value occurs at x = 1/3
The relative extreme values occur at x = 0 and 1/3
The relative extreme values occur at x = 1/2
There are no relative extreme values.
Answer:
The relative extreme values occur at x = ?1/2??.
Step-by-step explanation
f(x) = 3x4 - 2x3 - 1
The critical values occur at values of x where the first derivative of the function is 0.
i.e, f'(x) = 0
?dxd??(3x4 - 2x3 - 1) = 0
3* 4x3 - 2* 3x2 - 0 = 0
12x3 - 6x2 = 0
6x2(2x - 1) = 0
=> x = 0 and
(2x - 1) = 0, x = ?21??
Therefore x = 0 and x = ?21?? are the critical point.
Second derivative test:
For relative extreme, the second derivative must not equal 0.
Wherever the second derivative is 0, the point is an inflection point.
f"(x) = ?dxd??f'(x) = ?dxd??(12x3 - 6x2) = 12* 3x2 - 6*2x = 36x2 - 12x
---> At x = 0,
f"(0) = 36*0 - 12*0 = 0
The second derivative is 0, therefore at this value relative extreme will not occur.
----> At x = 1/2,
f(1/2) = 36*(??21??)2 - 12 * ??21?? = 9 - 6 = 3
The second derivative is not equal to 0, therefore at this value of x, relative extreme will occur.
Answer:
The relative extreme values occur at x = ?1/2.