Question
A I only
B ii ONLY
C III only
D I and III only
▶️Answer/Explanation
Ans:B
Since f′(1)=0 and f′′(1)<0, there is a relative maximum at x=1 by the Second Derivative Test. Therefore, statement II is true.Statement I is false since there is a relative maximum at
.Statement III is false since f′(4)=0 and f′′(4)>0 imply that there is a relative minimum at x=4 by the Second Derivative Test, not a relative maximum.
Question
Let
be a twice-differentiable function. Selected values of f
and f
are shown in the table above. Which of the following statements are true?
has neither a relative minimum nor a relative maximum at x=2.
II. f has a relative maximum x=2.
III. f has a relative maximum x=8.
A I only
B II only
C III only
D I and III only
▶️Answer/Explanation
Ans:B
Since f′(2)=0 and f′′(2)<0, there is a relative maximum at x=2 by the Second Derivative Test. Therefore, statement II is true.Statement I is false since there is a relative maximum at
.Statement III is false since f′(8)=0and f′′(8)>0 implies that there is a relative minimum at x=8 by the Second Derivative Test, not a relative maximum.
Question
The derivative of
\(f(x)=\frac{x^{4}}{3}-\frac{x^{5}}{5}\) attains its maximum value at x =
(A) –1 (B) 0 (C) 1 (D)\(-\frac{1}{8} \) (E)\(-\frac{1}{2}\)
▶️Answer/Explanation
Ans:C
Question
An equation of the line tangent to \(y=x^{3}+3x^{2}+2\) at its point of inflection is
(A)y=-6x-6 (B)y=-3x+1 (C)y=2x+10 (D)y=3x-1 (E)y=4x+1
▶️Answer/Explanation
Ans:E