泰勒 ln(cos(x))

解答

泰勒

ln (cos (x))

- \frac{1}{2} x^{2} - \frac{1}{12} x^{4} - \frac{1}{45} x^{6} - \frac{17}{2520} x^{8} - \frac{31}{14175} x^{10} + \dots

求解步骤

应用泰勒公式

= 0 + \frac{\frac{d}{d x} ( ln ( cos ( x ) ) ) ( 0 )}{1 !} x + \frac{\frac{d ^{2}}{d x ^{2}} ( ln ( cos ( x ) ) ) ( 0 )}{2 !} x^{2} + \frac{\frac{d ^{3}}{d x ^{3}} ( ln ( cos ( x ) ) ) ( 0 )}{3 !} x^{3} + \dots

求导数

= 0 + \frac{0}{1 !} x + \frac{- 1}{2 !} x^{2} + \frac{0}{3 !} x^{3} + \frac{- 2}{4 !} x^{4} + \frac{0}{5 !} x^{5} + \frac{- 16}{6 !} x^{6} + \frac{0}{7 !} x^{7} + \frac{- 272}{8 !} x^{8} + \frac{0}{9 !} x^{9} + \frac{- 7936}{10 !} x^{10} + \dots

整理后得

= - \frac{1}{2} x^{2} - \frac{1}{12} x^{4} - \frac{1}{45} x^{6} - \frac{17}{2520} x^{8} - \frac{31}{14175} x^{10} + \dots

\frac{d y}{d x} = \frac{x}{36 y}

in v erse l a pl a ce \frac{8}{s ^{2} + 64}

\int csc (\frac{x}{2}) d x

\frac{\partial}{\partial y} (10 x y)

d er i v a t i v e \frac{1}{x ^{2} - 2 x - 3}