展开 (4-1/x)^2

解答

展开

(4 - \frac{1}{x})^{2}

\frac{16 x ^{2} - 8 x + 1}{x ^{2}}

求解步骤

(4 - \frac{1}{x})^{2}

使用完全平方公式:

(a - b)^{2} = a^{2} - 2 ab + b^{2}

(4 - \frac{1}{x})^{2} = 4^{2} - 2 \cdot 4 \cdot \frac{1}{x} + (\frac{1}{x})^{2}

= 4^{2} - 2 \cdot 4 \cdot \frac{1}{x} + (\frac{1}{x})^{2}

化简

4^{2} - 2 \cdot 4 \cdot \frac{1}{x} + (\frac{1}{x})^{2} : \frac{16 x ^{2} - 8 x + 1}{x ^{2}}

= \frac{16 x ^{2} - 8 x + 1}{x ^{2}}

e x p an d \frac{720}{( 3 - 1 ) ^{7}} + sin (3 - 1)

e x p an d \frac{6}{2}

e x p an d 3 (6 y ln (y) + y^{5})

e x p an d β (3 x + 1, y)

e x p an d - \frac{- x ^{2} + 1}{( x ^{2} + 1 ) ^{2}}