展开 cos(1/(n^2))-cos(1/((n+1)^2))

解答

展开

cos (\frac{1}{n ^{2}}) - cos (\frac{1}{( n + 1 ) ^{2}})

cos (\frac{1}{n ^{2}}) - cos (\frac{1}{n ^{2} + 2 n + 1})

求解步骤

cos (\frac{1}{n ^{2}}) - cos (\frac{1}{( n + 1 ) ^{2}})

\frac{1}{( n + 1 ) ^{2}} = \frac{1}{n ^{2} + 2 n + 1}

= cos (\frac{1}{n ^{2}}) - cos (\frac{1}{n ^{2} + 2 n + 1})

e x p an d \frac{x + 4}{( x + 2 ) ( x - 3 )}

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

e x p an d \frac{2 e ^{- 2 s}}{s ^{2} ( 4 s + 1 )}

e x p an d \frac{3 x + 2 + ( 7 x - 1 ) 2}{4}

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