Ta có: f(x)-g(x)=3x2-5x4+x2-1+x-(x-x3+x4-2x2)
f(x)-g(x)=3x2-5x4+x2-1+x-x+x3-x4+2x2+\(\frac{1}{2}\) f(x)-g(x)=6x2+x3-6x4-\(\frac{1}{2}\)Vậy f(x)-g(x)=6x2+x3-6x4-\(\frac{1}{2}\)f (x) - g(x) = \(3x^2-5x^4+x^2-1+x-\left(x-x^3+x^4-2x^2-\frac{1}{2}\right)\)
= \(3x^2-5x^4+x^2-1+x-x+x^3-x^4+2x^2+\frac{1}{2}=-6x^4+x^3+6x^2-\frac{1}{2}\)
Ta có : f(x) = 3x2 - 5x4 +x2 - 1 + x = (3x2 +x2 ) - 5x4 - 1
g(x) = x - x3 +x4 - 2x2 - \(\frac{1}{2}\)
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f(x) = 4x2 - 5x4 - 1
g(x) = -2x2 +x4 - \(\frac{1}{2}\) +x -x3
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= 6x2 - 4x4 -1/2 +x -x3
Ta có: f(x) - g(x) = ( 3x2 - 5x4 + x2 -1 + x) - ( x - x3 + x4 - 2x2 - 1/2)
= 3x2 - 5x4 + x2 - 1 + x - x + x3 - x4 + 2x2 + 1/2
= (-5x4 - x4 ) - ( 3x2 + x2 + 2x2 ) - ( x - x ) + x3 - 1 + 1/2
= -6x4 + x3- 6x2 - 1/2
f(x) = 5x4 + 0x3 + 3x2 + x2 + x - 1
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g(x) = x4 - x3 - 2x2 + 0x2 + x - \(\dfrac{1}{2}\)
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f(x) - g(x)= 4x4 - x3 + 6x2 + 0x - \(\dfrac{1}{2}\)