展开 ((-1)^n(7n+5))/((5n^2-4n+3))

解答

展开

\frac{( - 1 ) ^{n} ( 7 n + 5 )}{( 5 n ^{2} - 4 n + 3 )}

\frac{7 ( - 1 ) ^{n} n + 5 ( - 1 ) ^{n}}{5 n ^{2} - 4 n + 3}

求解步骤

\frac{( - 1 ) ^{n} ( 7 n + 5 )}{5 n ^{2} - 4 n + 3}

乘开

(- 1)^{n} (7 n + 5) : 7 (- 1)^{n} n + 5 (- 1)^{n}

= \frac{7 ( - 1 ) ^{n} n + 5 ( - 1 ) ^{n}}{5 n ^{2} - 4 n + 3}

e x p an d cso l v e (0 = x^{4} - 32 x^{2} - 144, x)

e x p an d (5 t - t^{2}, t - (1 - t)^{2}, 1 - t - (5 t)^{2}) \cdot (5, 1, - 1)

e x p an d π (2 - 3)

e x p an d (\frac{( \frac{2 y + 3}{2} )}{2})^{2}

s im pl i f y (x - 1 + 3) \cdot (x - 1 - 3)