4 EXAMPLES OF SUCCESSIVE DIFFERENTIATION. 



d'v 

 6. If y = e~* cos x, - + ty = 0. 



7 



8. 



9 

 y. 



10 

 11. 



12. If^ = 6 z ^, = - 



da? 2a,y# 



13 



14. If y 2 = sec 2x, 

 15. 



ac b-ac 



17. If y = x n sin x, 



i n = w < sin # -}- x sin I a/ -f~ I -i . >/ 0*^1 1 *< n - 



rflr [ lV 2 / \.2 



n (w 1) (n 



n(n\).. 

 / 





18. If ^ = tan' 1 -, 

 a a 



then -^ = g a = cos 8 ^, 



ax a +yf a 



