Odpowiedź:
zad 7
a)
f(x) = x² - x - 2
a = 1 , b = - 1 , c = - 2
Δ = b² - 4ac = (- 1)² - 4 * 1 * (- 2) = 1 + 8 = 9
Obliczamy współrzędne wierzchołka
W = (- b/2a , - Δ/4a)
- b/2a = 1/2
- Δ/4a = - 9/4 = - 2 1/4
W = ( 1/2 , - 2 1/4)
xs - równanie osi symetrii = - b/2a = 1/2
f(- 2) = (- 2)² - (- 2) - 2 = 4 + 2 - 2 = 4
f(- 1) = (- 1)² - (- 1) - 2 = 1 + 1 - 2 = 2 - 2 = 0
f(1) = 1² - 1 - 2 = 1 - 1 - 2 = - 2
f(2) = 2² - 2 - 2 = 4 - 4 = 0
b)
f(x) = 2x² - 6x - 2
a = 2 , b = - 6 , c = - 2
Δ = b² - 4ac = (- 6)² - 4 * 2 * (- 2) = 36 + 16 = 52
- b/2a = 6/4 = 1 2/4 = 1 1/2
- Δ/4a = - 52/8 = - 6 4/8 = - 6 1/2
W = ( 1 1/2 , - 6 1/2 )
xs - równanie osi symetrii = - b/2a = 1 1/2
f(- 2) = 2 * (- 2)² - 6 * (- 2) - 2 = 2 * 4 + 12 - 2 = 8 + 12 - 2 = 18
f( - 1) = 2 * (- 1)² - 6 * (- 1) - 2 = 2 * 1 + 6 - 2 = 5
f(1) = 2 * 1² - 6 * 1 - 2 = 2 - 6 - 2 = - 6
f(2) = 2 * 2² - 6 * 2 - 2 = 2 * 4 - 12 - 2 = 8 - 12 - 2 = - 6
c)
f(x) = - 2x² + 6x - 4
a = - 2 , b = 6 , c = - 4
Δ = b² - 4ac = 6² - 4 * (- 2) * (- 4) = 36 - 32 = 4
Obliczamy współrzędne wierzchołka paraboli
- b/2a = - 6/( - 4) = 6/4 = 1 2/4 = 1 1/2
- Δ/4a = - 4/(- 8) = 4/8 = 1/2
W = ( 1 1/2 , 1/2 )
f(- 2) = - 2 * (- 2)² + 6 * (- 2) - 4 = - 2 * 4 - 12 - 4 = - 8 - 12 - 4 = - 20
f(- 1) = - 2 * (- 1)² + 6 * (- 1) - 4 = - 2 * 1 - 6 - 4 = - 2 - 10 = - 8
f(1) = - 2 * 1² + 6 * 1 - 4 = - 2 + 6 - 4 = 0
f(2) = - 2 * 2² + 6 * 2 - 4 = - 2 * 4 + 12 - 4 = - 8 + 12 - 4 = 0
d)
f(x) = - 6x² - 6x + 8
a = - 6 , b = - 6 , c = 8
Δ = b² - 4ac = (- 6)² - 4 * (- 6) * 8 = 36 + 192 = 228
- b/2a = 6/(- 12) = - 6/12 = - 1/2
- Δ/4a = - 228/(- 24) = 228/24 = 9 12/24 = 9 1/2
W = (- 1/2 , 9 1/2)
xs - równanie osi symetrii = - b/2a = - 1/2
f(- 2) = - 6 * (- 2)² - 6 * (- 2) + 8 = - 6 * 4 + 12 + 8 = - 24 + 20 = - 4
f( - 1) = - 6 * (- 1)² - 6 * (- 1) + 8 = - 6 * 1 + 6 + 8 = - 6 + 14 = 8
f(1) = - 6 * 1² - 6 * 1 + 8 = - 6 - 6 + 8 = - 4
f(2) = - 6 * 2² - 6 * 2 + 8 = - 6 * 4 - 12 + 8 = - 24 - 12 + 8 = - 26
" Life is not a problem to be solved but a reality to be experienced! "
© Copyright 2013 - 2024 KUDO.TIPS - All rights reserved.
Odpowiedź:
zad 7
a)
f(x) = x² - x - 2
a = 1 , b = - 1 , c = - 2
Δ = b² - 4ac = (- 1)² - 4 * 1 * (- 2) = 1 + 8 = 9
Obliczamy współrzędne wierzchołka
W = (- b/2a , - Δ/4a)
- b/2a = 1/2
- Δ/4a = - 9/4 = - 2 1/4
W = ( 1/2 , - 2 1/4)
xs - równanie osi symetrii = - b/2a = 1/2
f(- 2) = (- 2)² - (- 2) - 2 = 4 + 2 - 2 = 4
f(- 1) = (- 1)² - (- 1) - 2 = 1 + 1 - 2 = 2 - 2 = 0
f(1) = 1² - 1 - 2 = 1 - 1 - 2 = - 2
f(2) = 2² - 2 - 2 = 4 - 4 = 0
b)
f(x) = 2x² - 6x - 2
a = 2 , b = - 6 , c = - 2
Δ = b² - 4ac = (- 6)² - 4 * 2 * (- 2) = 36 + 16 = 52
Obliczamy współrzędne wierzchołka
W = (- b/2a , - Δ/4a)
- b/2a = 6/4 = 1 2/4 = 1 1/2
- Δ/4a = - 52/8 = - 6 4/8 = - 6 1/2
W = ( 1 1/2 , - 6 1/2 )
xs - równanie osi symetrii = - b/2a = 1 1/2
f(- 2) = 2 * (- 2)² - 6 * (- 2) - 2 = 2 * 4 + 12 - 2 = 8 + 12 - 2 = 18
f( - 1) = 2 * (- 1)² - 6 * (- 1) - 2 = 2 * 1 + 6 - 2 = 5
f(1) = 2 * 1² - 6 * 1 - 2 = 2 - 6 - 2 = - 6
f(2) = 2 * 2² - 6 * 2 - 2 = 2 * 4 - 12 - 2 = 8 - 12 - 2 = - 6
c)
f(x) = - 2x² + 6x - 4
a = - 2 , b = 6 , c = - 4
Δ = b² - 4ac = 6² - 4 * (- 2) * (- 4) = 36 - 32 = 4
Obliczamy współrzędne wierzchołka paraboli
W = (- b/2a , - Δ/4a)
- b/2a = - 6/( - 4) = 6/4 = 1 2/4 = 1 1/2
- Δ/4a = - 4/(- 8) = 4/8 = 1/2
W = ( 1 1/2 , 1/2 )
xs - równanie osi symetrii = - b/2a = 1 1/2
f(- 2) = - 2 * (- 2)² + 6 * (- 2) - 4 = - 2 * 4 - 12 - 4 = - 8 - 12 - 4 = - 20
f(- 1) = - 2 * (- 1)² + 6 * (- 1) - 4 = - 2 * 1 - 6 - 4 = - 2 - 10 = - 8
f(1) = - 2 * 1² + 6 * 1 - 4 = - 2 + 6 - 4 = 0
f(2) = - 2 * 2² + 6 * 2 - 4 = - 2 * 4 + 12 - 4 = - 8 + 12 - 4 = 0
d)
f(x) = - 6x² - 6x + 8
a = - 6 , b = - 6 , c = 8
Δ = b² - 4ac = (- 6)² - 4 * (- 6) * 8 = 36 + 192 = 228
Obliczamy współrzędne wierzchołka
W = (- b/2a , - Δ/4a)
- b/2a = 6/(- 12) = - 6/12 = - 1/2
- Δ/4a = - 228/(- 24) = 228/24 = 9 12/24 = 9 1/2
W = (- 1/2 , 9 1/2)
xs - równanie osi symetrii = - b/2a = - 1/2
f(- 2) = - 6 * (- 2)² - 6 * (- 2) + 8 = - 6 * 4 + 12 + 8 = - 24 + 20 = - 4
f( - 1) = - 6 * (- 1)² - 6 * (- 1) + 8 = - 6 * 1 + 6 + 8 = - 6 + 14 = 8
f(1) = - 6 * 1² - 6 * 1 + 8 = - 6 - 6 + 8 = - 4
f(2) = - 6 * 2² - 6 * 2 + 8 = - 6 * 4 - 12 + 8 = - 24 - 12 + 8 = - 26