All flashcards Flashcard 1: Find f ′ ( x ) f'(x) f ′ ( x ) for f ( x ) = 2 x 3 − 3 x 2 − 12 x + 1 f(x) = 2x^3 - 3x^2 - 12x + 1 f ( x ) = 2 x 3 − 3 x 2 − 12 x + 1 . Answer: f ′ ( x ) = 6 x 2 − 6 x − 12 f'(x) = 6x^2 - 6x - 12 f ′ ( x ) = 6 x 2 − 6 x − 12 . Use power rule: 6 x 2 6x^2 6 x 2 from 2 x 3 2x^3 2 x 3 , − 6 x -6x − 6 x from − 3 x 2 -3x^2 − 3 x 2 .
Flashcard 2: Identify the critical points of f ( x ) = 2 x 3 − 3 x 2 − 12 x + 1 f(x) = 2x^3 - 3x^2 - 12x + 1 f ( x ) = 2 x 3 − 3 x 2 − 12 x + 1 . Answer: Critical points: x = − 1 , 2 x = -1, 2 x = − 1 , 2 . Solve 6 x 2 − 6 x − 12 = 6 ( x 2 − x − 2 ) = 0 6x^2 - 6x - 12 = 6(x^2 - x - 2) = 0 6 x 2 − 6 x − 12 = 6 ( x 2 − x − 2 ) = 0 .
Flashcard 3: Determine the intervals where f ( x ) = x 3 − 3 x 2 + 2 f(x) = x^3 - 3x^2 + 2 f ( x ) = x 3 − 3 x 2 + 2 is increasing. Answer: Increasing on ( 2 , infinity ) (2, \, \text{infinity}) ( 2 , infinity ) . f ′ ( x ) > 0 f'(x) > 0 f ′ ( x ) > 0 when x > 2 x > 2 x > 2 (test a point like x = 3 x = 3 x = 3 ).
Flashcard 4: Determine the intervals where f ( x ) = x 3 − 3 x 2 + 2 f(x) = x^3 - 3x^2 + 2 f ( x ) = x 3 − 3 x 2 + 2 is decreasing. Answer: Decreasing on ( − infinity , 0 ) (-\text{infinity}, 0) ( − infinity , 0 ) and ( 0 , 2 ) (0, 2) ( 0 , 2 ) .. f ′ ( x ) < 0 f'(x) < 0 f ′ ( x ) < 0 when x < 0 x < 0 x < 0 or 0 < x < 2 0 < x < 2 0 < x < 2 .
Flashcard 5: What does f ′ ( x ) < 0 f'(x) < 0 f ′ ( x ) < 0 indicate about a function on an interval? Answer: The function is decreasing on that interval. Negative derivative means the function has negative slope.
Flashcard 6: What is the relative extrema at x = π x = \pi x = π for f ( x ) = cos x f(x) = \cos x f ( x ) = cos x ? Answer: Relative minimum. f ′ f' f ′ changes from negative to positive at x = π x = \pi x = π .
Flashcard 7: Identify the critical points of f ( x ) = cos x f(x) = \cos x f ( x ) = cos x on [ 0 , 2 \backslashpi ] [0, 2\backslashpi] [ 0 , 2 \backslashpi ] . Answer: Critical points: x = π x = \pi x = π . − sin x = 0 -\sin x = 0 − sin x = 0 when x = π x = \pi x = π in the given interval.
Flashcard 8: Identify the critical points of f ( x ) = 1 4 x 4 − x 2 + 2 f(x) = \frac{1}{4}x^4 - x^2 + 2 f ( x ) = 4 1 x 4 − x 2 + 2 . Answer: Critical points: x = 0 , ± 1 x = 0, \pm 1 x = 0 , ± 1 . Solve x 3 − 2 x = x ( x 2 − 2 ) = 0 x^3 - 2x = x(x^2 - 2) = 0 x 3 − 2 x = x ( x 2 − 2 ) = 0 .
Flashcard 9: What is the relative extrema at x = − 2 x = -\sqrt{2} x = − 2 for f ( x ) = 1 3 x 3 − 2 x + 1 f(x) = \frac{1}{3}x^3 - 2x + 1 f ( x ) = 3 1 x 3 − 2 x + 1 ? Answer: Relative maximum. f ′ f' f ′ changes from positive to negative at x = − 2 x = -\sqrt{2} x = − 2 .
Flashcard 10: What is the relative extrema at x = π 2 x = \frac{\pi}{2} x = 2 π for f ( x ) = sin x f(x) = \sin x f ( x ) = sin x ? Answer: Relative maximum. f ′ f' f ′ changes from positive to negative at x = π 2 x = \frac{\pi}{2} x = 2 π .
Flashcard 11: What is the relative extrema at x = 3 π 2 x = \frac{3\pi}{2} x = 2 3 π for f ( x ) = sin x f(x) = \sin x f ( x ) = sin x ? Answer: Relative minimum. f ′ f' f ′ changes from negative to positive at x = 3 π 2 x = \frac{3\pi}{2} x = 2 3 π .
Flashcard 12: Find f ′ ( x ) f'(x) f ′ ( x ) for f ( x ) = 1 4 x 4 − x 2 + 2 f(x) = \frac{1}{4}x^4 - x^2 + 2 f ( x ) = 4 1 x 4 − x 2 + 2 . Answer: f ′ ( x ) = x 3 − 2 x f'(x) = x^3 - 2x f ′ ( x ) = x 3 − 2 x . Derivative of 1 4 x 4 \frac{1}{4}x^4 4 1 x 4 is x 3 x^3 x 3 , of x 2 x^2 x 2 is 2 x 2x 2 x .
Flashcard 13: Determine the critical points of f ( x ) = 1 3 x 3 − 2 x + 1 f(x) = \frac{1}{3}x^3 - 2x + 1 f ( x ) = 3 1 x 3 − 2 x + 1 . Answer: Critical points: x = ± 2 x = \pm \sqrt{2} x = ± 2 . Solve x 2 − 2 = 0 x^2 - 2 = 0 x 2 − 2 = 0 to get x 2 = 2 x^2 = 2 x 2 = 2 .
Flashcard 14: Find the critical points of f ( x ) = x 2 + 4 x + 4 f(x) = x^2 + 4x + 4 f ( x ) = x 2 + 4 x + 4 . Answer: Critical point: x = − 2 x = -2 x = − 2 . f ′ ( x ) = 2 x + 4 = 0 f'(x) = 2x + 4 = 0 f ′ ( x ) = 2 x + 4 = 0 gives x = − 2 x = -2 x = − 2 .
Flashcard 15: What is the relative extrema at x = 2 x = 2 x = 2 for f ( x ) = x 3 − 3 x 2 + 2 f(x) = x^3 - 3x^2 + 2 f ( x ) = x 3 − 3 x 2 + 2 ? Answer: Relative minimum. f ′ f' f ′ changes from negative to positive at x = 2 x = 2 x = 2 .
Flashcard 16: Find the derivative of f ( x ) = x 3 − 3 x 2 + 2 f(x) = x^3 - 3x^2 + 2 f ( x ) = x 3 − 3 x 2 + 2 . Answer: f ′ ( x ) = 3 x 2 − 6 x f'(x) = 3x^2 - 6x f ′ ( x ) = 3 x 2 − 6 x . Use power rule: derivative of x 3 x^3 x 3 is 3 x 2 3x^2 3 x 2 , x 2 x^2 x 2 is 2 x 2x 2 x .
Flashcard 17: Find the critical points of f ( x ) = x 3 − 3 x 2 + 2 f(x) = x^3 - 3x^2 + 2 f ( x ) = x 3 − 3 x 2 + 2 . Answer: Critical points: x = 0 , x = 2 x = 0, x = 2 x = 0 , x = 2 . Set f ′ ( x ) = 3 x 2 − 6 x = 3 x ( x − 2 ) = 0 f'(x) = 3x^2 - 6x = 3x(x-2) = 0 f ′ ( x ) = 3 x 2 − 6 x = 3 x ( x − 2 ) = 0 .
Flashcard 18: Identify the type of extrema at a critical point if f ′ f' f ′ changes from positive to negative. Answer: Relative maximum. Function rises then falls, creating a local peak.
Flashcard 19: State the condition for a critical point of a function. Answer: The derivative f ′ ( x ) = 0 f'(x) = 0 f ′ ( x ) = 0 or f ′ ( x ) f'(x) f ′ ( x ) is undefined. Critical points occur where the slope is zero or undefined.
Flashcard 20: What is the First Derivative Test used for in calculus? Answer: To determine relative (local) extrema of a function. Identifies where functions reach local peaks and valleys.
Flashcard 21: What is the relative extrema at x = 2 x = 2 x = 2 for f ( x ) = 2 x 3 − 3 x 2 − 12 x + 1 f(x) = 2x^3 - 3x^2 - 12x + 1 f ( x ) = 2 x 3 − 3 x 2 − 12 x + 1 ? Answer: Relative minimum. f ′ f' f ′ changes from negative to positive at x = 2 x = 2 x = 2 .
Flashcard 22: Identify the type of extrema at a critical point if f ′ f' f ′ changes from negative to positive. Answer: Relative minimum. Function falls then rises, creating a local valley.
Flashcard 23: What is the relative extrema at x = − 1 x = -1 x = − 1 for f ( x ) = 2 x 3 − 3 x 2 − 12 x + 1 f(x) = 2x^3 - 3x^2 - 12x + 1 f ( x ) = 2 x 3 − 3 x 2 − 12 x + 1 ? Answer: Relative maximum. f ′ f' f ′ changes from positive to negative at x = − 1 x = -1 x = − 1 .
Flashcard 24: Find the derivative of f ( x ) = 1 3 x 3 − 2 x + 1 f(x) = \frac{1}{3}x^3 - 2x + 1 f ( x ) = 3 1 x 3 − 2 x + 1 . Answer: f ′ ( x ) = x 2 − 2 f'(x) = x^2 - 2 f ′ ( x ) = x 2 − 2 . Use power rule on each term of the polynomial.
Flashcard 25: What conclusion is drawn if f ′ ( x ) f'(x) f ′ ( x ) does not change sign at a critical point? Answer: No relative extrema at that point. No sign change means no local maximum or minimum.
Flashcard 26: Find the derivative of f ( x ) = sin x f(x) = \sin x f ( x ) = sin x . Answer: f ′ ( x ) = cos x f'(x) = \cos x f ′ ( x ) = cos x . Derivative of sine function is cosine.
Flashcard 27: What does f ′ ( x ) > 0 f'(x) > 0 f ′ ( x ) > 0 indicate about a function on an interval? Answer: The function is increasing on that interval. Positive derivative means the function has positive slope.
Flashcard 28: State the derivative of f ( x ) = cos x f(x) = \cos x f ( x ) = cos x . Answer: f ′ ( x ) = − sin x f'(x) = -\sin x f ′ ( x ) = − sin x . Derivative of cosine function is negative sine.
Flashcard 29: Determine the intervals where f ( x ) = cos x f(x) = \cos x f ( x ) = cos x is decreasing on [ 0 , 2 π ] [0, 2\pi] [ 0 , 2 π ] . Answer: Decreasing on ( 0 , π ) (0, \pi) ( 0 , π ) . − sin x < 0 -\sin x < 0 − sin x < 0 when 0 < x < π 0 < x < \pi 0 < x < π .
Flashcard 30: What is the relative extrema at x = − 2 x = -2 x = − 2 for f ( x ) = x 2 + 4 x + 4 f(x) = x^2 + 4x + 4 f ( x ) = x 2 + 4 x + 4 ? Answer: Relative minimum. f ′ f' f ′ changes from negative to positive at x = − 2 x = -2 x = − 2 .