x/x^2-x+1=7
分子分母同时除以x,得
1/(x-1+1/x)=7
x-1+1/x=1/7
x + 1/x =8/7
平方得
(x + 1/x)² =(8/7)²=64/49
x² + 2 + 1/x² = 64/49
x² +1 + 1/x² = 15/49
求倒数
1/(x² +1 + 1/x²)= 49/15
分子分母同时乘以x²,得
x^2/x^4+x^2+1=49/15
答:
x^2/x^4+x^2+1=49/15
x/x^2-x+1=7
求倒数:
x^2-x+1/x=7
x + 1/x =8/7
平方得
(x + 1/x)² =(8/7)²=64/49
x² + 2 + 1/x² = 64/49
x² +1 + 1/x² = 15/49
求倒数
1/(x² +1 + 1/x²)= 49/15
分子分母同时乘以x²,得
x^2/x^4+x^2+1=49/15
答:
x^2/x^4+x^2+1=49/15
x/x^2-x+1=7
分子分母同时除以x,得
1/(x-1+1/x)=7
x-1+1/x=1/7
x + 1/x =8/7
平方得
(x + 1/x)² =(8/7)²=64/49
x² + 2 + 1/x² = 64/49
x² +1 + 1/x² = 15/49
求倒数
1/(x² +1 + 1/x²)= 49/15
分子分母同时乘以x²,得
x^2/x^4+x^2+1=49/15
猪头三