Đáp án:
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`a,`
`K (y) = y^4 + 4y^3 + 2y^2 - 4y + 1`
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Với `y=-2`
`-> K (-2) = (-2)^4 + 4 . (-2)^3 + 2 . (-2)^2 - 4 . (-2) + 1`
`-> K (-2) = 16 + 4 . (-8) + 2 . 4 - (-8) + 1`
`-> K (-2) = 16 + (-32) + 8 + 8 + 1`
`-> K (-2) = -16 + 8 + 8 + 1`
`-> K (-2) = -8 + 8 + 1`
`-> K (-2) = 0 + 1`
`-> K (-2) = 1`
Vậy `K (-2) = 1`
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Với `y = 1`
`-> K (1) =1^4 + 4 . 1^3 + 2 . 1^2 - 4 . 1 + 1`
`-> K (1) = 1 + 4 . 1 + 2 . 1 - 4 + 1`
`-> K (1) = 1 + 4 + 2 - 4 + 1`
`-> K (1) =5 + 2 - 4 + 1`
`-> K (1) = 7 -4 + 1`
`-> K (1) = 3 + 1`
`-> K (1) =4`
Vậy `K (1) =4`
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Với `y = 1/3`
`-> K (1/3) = (1/3)^4 + 4 . (1/3)^3 + 2 . (1/3)^2 + 4 . 1/3 + 1`
`-> K (1/3) = 1/81 + 4 . 1/27 + 2 . 1/9 -4/3 + 1`
`-> K (1/3) = 1/81 + 4/27 + 2/9 - 4/3 + 1`
`-> K (1/3) = 13/81 + 2/9 - 4/3 +1`
`-> K (1/3) = 31/81 -4/3 + 1`
`-> K (1/3) = (-77)/81 + 1`
`-> K (1/3) =4/81`
Vậy `K (1/3) =4/81`
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`b,`
`H (x) = x^4 + 2x^2 + 1`
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Với `x = 0`
`-> H (0) = 0^4 + 2 . 0^2 + 1`
`-> H (0) = 0 + 2 . 0 + 1`
`-> H (0) = 0 + 2 + 1`
`-> H (0) = 2 + 1`
`->H (0) = 3`
Vậy `H (0) =3`
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Với `x=-1`
`-> H (-1) = (-1)^4 + 2 . (-1)^2 + 1`
`-> H (-1) = 1 + 2 . 1 + 1`
`-> H (-1) = 1 + 2 + 1`
`-> H (-1) =3 + 1`
`-> H (-1) =4`
Vậy `H (-1) = 4`
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Với `x=1/2`
`-> H (1/2) = (1/2)^4 + 2 . (1/2)^2 +1`
`-> H (1/2) = 1/16 + 2 . 1/4 + 1`
`-> H (1/2) = 1/16 + 1/2 + 1`
`-> H (1/2) = 9/16 + 1`
`-> H (1/2) = 25/16`
Vậy `H (1/2) = 25/16`
