INFINITE SERIES 



127 



CO 



a* 



2! ' 4! ' 6! ' ' ' - j(2n)\ 



w=o 

 I 2 17 



3. tanh x = x x 3 + x b x 7 4- . 



3 15 3i5 



4. # coth x = i + ~ a 2 - # 4 + 

 3 45 945 



, 

 o 360 15120 



5. 



6. x csch 



6.475 



I. COSh COS X = I -- : X- 4 + X 8 - : .t 12 + . . 



4! 8! 12! 



2. sinh x sin x = ; x 2 x 6 4- : x w 

 2! 6! 10! 



6.476 



I. e xcos8 CQS ( x s j n 0) _ 



/} / /3\ 



2. e xcos0 sm (xsm 0) 



, i m / m "^ 



3. cosh (* cos 6) cos (as sin u) = 7. 



m / /i\ 



4. smh (# cos d) - cos (# sin 6) = 



m 



5. cosh cos 0) sin sm 0) ~ 



6. sinh ( cos 6) sin (# sin 6) = 



[^<T] 



