All flashcards Flashcard 1: What is the formula for the backward difference quotient to estimate the derivative at a point? Answer: f ′ ( a ) ≈ f ( a ) − f ( a − h ) h f'(a) \approx \frac{f(a) - f(a-h)}{h} f ′ ( a ) ≈ h f ( a ) − f ( a − h ) . Uses the point before a a a to estimate the slope.
Flashcard 2: Estimate f ′ ( 3 ) f'(3) f ′ ( 3 ) for f ( x ) = tan − 1 ( x ) f(x) = \tan^{-1}(x) f ( x ) = tan − 1 ( x ) using h = 0.01 h = 0.01 h = 0.01 and the backward difference quotient. Answer: 0.0995. Backward formula: tan − 1 ( 3 ) − tan − 1 ( 2.99 ) 0.01 ≈ 0.0995 \frac{\tan^{-1}(3) - \tan^{-1}(2.99)}{0.01} \approx 0.0995 0.01 t a n − 1 ( 3 ) − t a n − 1 ( 2.99 ) ≈ 0.0995
Flashcard 3: Estimate f ′ ( 1 ) f'(1) f ′ ( 1 ) for f ( x ) = 2 x f(x) = 2^x f ( x ) = 2 x using h = 0.001 h = 0.001 h = 0.001 and the symmetric difference quotient. Answer: 1.3863. Symmetric formula: 2 1.001 − 2 0.999 0.002 ≈ 1.3863 \frac{2^{1.001} - 2^{0.999}}{0.002} \approx 1.3863 0.002 2 1.001 − 2 0.999 ≈ 1.3863
Flashcard 4: Estimate f ′ ( 0 ) f'(0) f ′ ( 0 ) for f ( x ) = log ( 1 + x ) f(x) = \log(1+x) f ( x ) = log ( 1 + x ) using h = 0.01 h = 0.01 h = 0.01 and the symmetric difference quotient. Answer: 0.9950. Symmetric formula: log ( 1.01 ) − log ( 0.99 ) 0.02 ≈ 0.9950 \frac{\log(1.01) - \log(0.99)}{0.02} \approx 0.9950 0.02 l o g ( 1.01 ) − l o g ( 0.99 ) ≈ 0.9950
Flashcard 5: Estimate f ′ ( 4 ) f'(4) f ′ ( 4 ) for f ( x ) = 1 x 3 f(x) = \frac{1}{x^3} f ( x ) = x 3 1 using h = 0.1 h = 0.1 h = 0.1 and the forward difference quotient. Answer: -0.0351. Forward formula: 1 / ( 4.1 ) 3 − 1 / 64 0.1 ≈ − 0.0351 \frac{1/(4.1)^3 - 1/64}{0.1} \approx -0.0351 0.1 1/ ( 4.1 ) 3 − 1/64 ≈ − 0.0351
Flashcard 6: Estimate f ′ ( 1 ) f'(1) f ′ ( 1 ) for f ( x ) = sin ( 2 x ) f(x) = \sin(2x) f ( x ) = sin ( 2 x ) using h = 0.001 h = 0.001 h = 0.001 and the symmetric difference quotient. Answer: 1.0806. Symmetric formula: sin ( 2.002 ) − sin ( 1.998 ) 0.002 ≈ 1.0806 \frac{\sin(2.002) - \sin(1.998)}{0.002} \approx 1.0806 0.002 s i n ( 2.002 ) − s i n ( 1.998 ) ≈ 1.0806
Flashcard 7: Estimate f ′ ( 2 ) f'(2) f ′ ( 2 ) for f ( x ) = tan x f(x) = \tan x f ( x ) = tan x using h = 0.01 h = 0.01 h = 0.01 and the forward difference quotient. Answer: 2.0199. Forward formula: tan ( 2.01 ) − tan ( 2 ) 0.01 ≈ 2.0199 \frac{\tan(2.01) - \tan(2)}{0.01} \approx 2.0199 0.01 t a n ( 2.01 ) − t a n ( 2 ) ≈ 2.0199
Flashcard 8: Estimate f ′ ( 1 ) f'(1) f ′ ( 1 ) for f ( x ) = x f(x) = \sqrt{x} f ( x ) = x using h = 0.001 h = 0.001 h = 0.001 and the backward difference quotient. Answer: 0.4995. Backward formula: 1 − 0.999 0.001 ≈ 0.4995 \frac{\sqrt{1} - \sqrt{0.999}}{0.001} \approx 0.4995 0.001 1 − 0.999 ≈ 0.4995
Flashcard 9: Estimate f ′ ( 5 ) f'(5) f ′ ( 5 ) for f ( x ) = log x f(x) = \log x f ( x ) = log x using h = 0.01 h = 0.01 h = 0.01 and the backward difference quotient. Answer: 0.1990. Backward formula: log ( 5 ) − log ( 4.99 ) 0.01 ≈ 0.1990 \frac{\log(5) - \log(4.99)}{0.01} \approx 0.1990 0.01 l o g ( 5 ) − l o g ( 4.99 ) ≈ 0.1990
Flashcard 10: What is the formula for the forward difference quotient to estimate the derivative at a point? Answer: f ′ ( a ) ≈ f ( a + h ) − f ( a ) h . U s e s t h e p o i n t a f t e r f'(a) \approx \frac{f(a+h) - f(a)}{h}. Uses the point after f ′ ( a ) ≈ h f ( a + h ) − f ( a ) . U ses t h e p o in t a f t er a$ to estimate the slope.
Flashcard 11: Estimate f ′ ( 0 ) f'(0) f ′ ( 0 ) for f ( x ) = cos x f(x) = \cos x f ( x ) = cos x using h = 0.01 h = 0.01 h = 0.01 and the forward difference quotient. Answer: -0.0005. Forward formula: cos ( 0.01 ) − cos ( 0 ) 0.01 ≈ − 0.0005 \frac{\cos(0.01) - \cos(0)}{0.01} \approx -0.0005 0.01 c o s ( 0.01 ) − c o s ( 0 ) ≈ − 0.0005
Flashcard 12: What is the impact of a smaller h h h on the accuracy of a derivative estimate? Answer: Increases accuracy. Smaller step sizes give more precise estimates.
Flashcard 13: Estimate f ′ ( 0 ) f'(0) f ′ ( 0 ) for f ( x ) = 1 1 + x f(x) = \frac{1}{1+x} f ( x ) = 1 + x 1 using h = 0.1 h = 0.1 h = 0.1 and the symmetric difference quotient. Answer: -0.9990. Symmetric formula: 1 / 1.1 − 1 / 0.9 0.2 ≈ − 0.9990 \frac{1/1.1 - 1/0.9}{0.2} \approx -0.9990 0.2 1/1.1 − 1/0.9 ≈ − 0.9990
Flashcard 14: Estimate f ′ ( 1 ) f'(1) f ′ ( 1 ) for f ( x ) = x ⋅ e x f(x) = x \cdot e^x f ( x ) = x ⋅ e x using h = 0.001 h = 0.001 h = 0.001 and the forward difference quotient. Answer: 5.4379. Forward formula: 1.001 ⋅ e 1.001 − e 0.001 ≈ 5.4379 \frac{1.001 \cdot e^{1.001} - e}{0.001} \approx 5.4379 0.001 1.001 ⋅ e 1.001 − e ≈ 5.4379
Flashcard 15: Estimate f ′ ( 2 ) f'(2) f ′ ( 2 ) for f ( x ) = ln ( 1 + x 2 ) f(x) = \ln(1+x^2) f ( x ) = ln ( 1 + x 2 ) using h = 0.1 h = 0.1 h = 0.1 and the symmetric difference quotient. Answer: 0.8000. Symmetric formula: ln ( 5.41 ) − ln ( 4.01 ) 0.2 ≈ 0.8000 \frac{\ln(5.41) - \ln(4.01)}{0.2} \approx 0.8000 0.2 l n ( 5.41 ) − l n ( 4.01 ) ≈ 0.8000
Flashcard 16: Estimate f ′ ( 3 ) f'(3) f ′ ( 3 ) for f ( x ) = x 2 + x f(x) = x^2 + x f ( x ) = x 2 + x using h = 0.1 h = 0.1 h = 0.1 and the symmetric difference quotient. Answer: 7.0. Symmetric formula gives exact derivative 2 x + 1 = 7 2x+1=7 2 x + 1 = 7 at x = 3 x=3 x = 3 .
Flashcard 17: Estimate f ′ ( 0 ) f'(0) f ′ ( 0 ) for f ( x ) = ln ( 1 + x ) f(x) = \ln(1+x) f ( x ) = ln ( 1 + x ) using h = 0.1 h = 0.1 h = 0.1 and the symmetric difference quotient. Answer: 0.9950. Symmetric formula: ln ( 1.1 ) − ln ( 0.9 ) 0.2 ≈ 0.9950 \frac{\ln(1.1) - \ln(0.9)}{0.2} \approx 0.9950 0.2 l n ( 1.1 ) − l n ( 0.9 ) ≈ 0.9950
Flashcard 18: Which difference quotient is more accurate: forward or symmetric? Answer: Symmetric. Averages left and right slopes for better approximation.
Flashcard 19: Estimate f ′ ( 1 ) f'(1) f ′ ( 1 ) for f ( x ) = e x f(x) = e^x f ( x ) = e x using h = 0.001 h = 0.001 h = 0.001 and the backward difference quotient. Answer: 2.718. Backward formula: e 1 − e 0.999 0.001 ≈ 2.718 \frac{e^1 - e^{0.999}}{0.001} \approx 2.718 0.001 e 1 − e 0.999 ≈ 2.718
Flashcard 20: Estimate f ′ ( 3 ) f'(3) f ′ ( 3 ) for f ( x ) = sin x f(x) = \sin x f ( x ) = sin x using h = 0.01 h = 0.01 h = 0.01 and the forward difference quotient. Answer: -0.9895. Forward formula: sin ( 3.01 ) − sin ( 3 ) 0.01 ≈ − 0.9895 \frac{\sin(3.01) - \sin(3)}{0.01} \approx -0.9895 0.01 s i n ( 3.01 ) − s i n ( 3 ) ≈ − 0.9895
Flashcard 21: Estimate f ′ ( 4 ) f'(4) f ′ ( 4 ) for f ( x ) = 1 x 2 f(x) = \frac{1}{x^2} f ( x ) = x 2 1 using h = 0.1 h = 0.1 h = 0.1 and the backward difference quotient. Answer: -0.1251. Backward formula: 1 / 16 − 1 / 15.21 0.1 ≈ − 0.1251 \frac{1/16 - 1/15.21}{0.1} \approx -0.1251 0.1 1/16 − 1/15.21 ≈ − 0.1251
Flashcard 22: Estimate f ′ ( 3 ) f'(3) f ′ ( 3 ) for f ( x ) = cos ( 2 x ) f(x) = \cos(2x) f ( x ) = cos ( 2 x ) using h = 0.01 h = 0.01 h = 0.01 and the backward difference quotient. Answer: -1.9159. Backward formula: cos ( 6 ) − cos ( 5.98 ) 0.01 ≈ − 1.9159 \frac{\cos(6) - \cos(5.98)}{0.01} \approx -1.9159 0.01 c o s ( 6 ) − c o s ( 5.98 ) ≈ − 1.9159
Flashcard 23: Estimate f ′ ( 2 ) f'(2) f ′ ( 2 ) for f ( x ) = 1 + x f(x) = \sqrt{1+x} f ( x ) = 1 + x using h = 0.1 h = 0.1 h = 0.1 and the symmetric difference quotient. Answer: 0.3536. Symmetric formula: 3.1 − 2.9 0.2 ≈ 0.3536 \frac{\sqrt{3.1} - \sqrt{2.9}}{0.2} \approx 0.3536 0.2 3.1 − 2.9 ≈ 0.3536
Flashcard 24: Estimate f ′ ( 2 ) f'(2) f ′ ( 2 ) for f ( x ) = x 3 − 3 x 2 + 2 x f(x) = x^3 - 3x^2 + 2x f ( x ) = x 3 − 3 x 2 + 2 x using h = 0.1 h = 0.1 h = 0.1 and the forward difference quotient. Answer: -2.999. Forward formula for f ′ ( x ) = 3 x 2 − 6 x + 2 f'(x) = 3x^2 - 6x + 2 f ′ ( x ) = 3 x 2 − 6 x + 2 at x = 2 x=2 x = 2 .
Flashcard 25: Which value of h h h gives a more accurate estimate: h = 0.1 h=0.1 h = 0.1 or h = 0.01 h=0.01 h = 0.01 ? Answer: h = 0.01 h=0.01 h = 0.01 . Smaller h h h values reduce approximation error.
Flashcard 26: Estimate f ′ ( 4 ) f'(4) f ′ ( 4 ) for f ( x ) = 1 x f(x) = \frac{1}{x} f ( x ) = x 1 using h = 0.1 h = 0.1 h = 0.1 and the forward difference quotient. Answer: -0.0625. Forward formula: 1 / 4.1 − 1 / 4 0.1 ≈ − 0.0625 \frac{1/4.1 - 1/4}{0.1} \approx -0.0625 0.1 1/4.1 − 1/4 ≈ − 0.0625
Flashcard 27: What is the formula to estimate the derivative of a function at a point using the symmetric difference quotient? Answer: f ′ ( a ) ≈ f ( a + h ) − f ( a − h ) 2 h f'(a) \approx \frac{f(a+h) - f(a-h)}{2h} f ′ ( a ) ≈ 2 h f ( a + h ) − f ( a − h ) . Uses points on both sides of a a a for better accuracy.
Flashcard 28: Identify the error: f ′ ( a ) ≈ f ( a + h ) + f ( a − h ) 2 h f'(a) \approx \frac{f(a+h) + f(a-h)}{2h} f ′ ( a ) ≈ 2 h f ( a + h ) + f ( a − h ) Answer: Correct: f ′ ( a ) ≈ f ( a + h ) − f ( a − h ) 2 h f'(a) \approx \frac{f(a+h) - f(a-h)}{2h} f ′ ( a ) ≈ 2 h f ( a + h ) − f ( a − h ) . Should subtract, not add, in the numerator.
Flashcard 29: Estimate f ′ ( 1 ) f'(1) f ′ ( 1 ) for f ( x ) = e − x f(x) = e^{-x} f ( x ) = e − x using h = 0.001 h = 0.001 h = 0.001 and the backward difference quotient. Answer: -0.368. Backward formula: e − 1 − e − 1.001 0.001 ≈ − 0.368 \frac{e^{-1} - e^{-1.001}}{0.001} \approx -0.368 0.001 e − 1 − e − 1.001 ≈ − 0.368
Flashcard 30: Estimate f ′ ( 2 ) f'(2) f ′ ( 2 ) for f ( x ) = x 2 f(x) = x^2 f ( x ) = x 2 using h = 0.01 h = 0.01 h = 0.01 and the symmetric difference quotient. Answer: 4.0001. Symmetric formula: ( 2.01 ) 2 − ( 1.99 ) 2 0.02 = 4.0001 \frac{(2.01)^2 - (1.99)^2}{0.02} = 4.0001 0.02 ( 2.01 ) 2 − ( 1.99 ) 2 = 4.0001