Bài 4: Cho các đa thức : A(x) = 3x6 – 5x4 +2x2– 7 B(x) = 8x6 + 7x4 – x2 + 11 C(x) = x6 + x4 – 8x2 + 6 Tính: A(x) + B(x); B(x) + C(x); A(x) + C(x) A(x) + B(x)- C(x); B(x) + C(x) – A(x); C(x) + A(x) – B(x); A(x) + B(x) +...
Đọc tiếp
Bài 4: Cho các đa thức : A(x) = 3x6 – 5x4 +2x2– 7 B(x) = 8x6 + 7x4 – x2 + 11 C(x) = x6 + x4 – 8x2 + 6
Tính: A(x) + B(x);
B(x) + C(x);
A(x) + C(x) A(x) + B(x)- C(x);
B(x) + C(x) – A(x); C(x) + A(x) – B(x);
A(x) + B(x) + C(x)
sửa hộ mình B(x) + C(x) là -9x^2
Ta có : \(B\left(x\right)+C\left(x\right)-A\left(x\right)\)
\(\Rightarrow9x^6+8x^4-9x^2+17-3x^6+5x^4+2x^2-7=6x^6+13x^4-7x^2+10\)
\(C\left(x\right)+A\left(x\right)-B\left(x\right)\)
\(\Rightarrow4x^6-4x^4-6x^2-1-8x^6-7x^4+x^2-11=-4x^6-11x^4-5x^2-12\)
\(A\left(x\right)+B\left(x\right)+C\left(x\right)\Rightarrow11x^6+2x^4+x^2+4+x^6+x^4-8x^2+6\)
\(=12x^6+3x^4-7x^2+10\)
Ta có : \(A\left(x\right)+B\left(x\right)\Rightarrow3x^6-5x^4+2x^2-7+8x^6+7x^4-x^2+11\)
\(=11x^6+2x^4+x^2+4\)
\(B\left(x\right)+C\left(x\right)\Rightarrow8x^6+7x^4-x^2+11+x^6+x^4-8x^2+6\)
\(=9x^6+8x^4-10x^2+17\)
\(A\left(x\right)+C\left(x\right)\Rightarrow3x^6-5x^4+2x^2-7+x^6+x^4-8x^2+6\)
\(=4x^6-4x^4-6x^2-1\)
\(B\left(x\right)-C\left(x\right)\Rightarrow8x^6+7x^4-x^2+11-x^6-x^4+8x^2-6\)
\(=7x^6+6x^4+7x^2+5\)