EXAMPLES OF DIFFERENTIAL COEFFICIENTS. 55 



67. y-=isnT 1 {x- 



. _, x tan a dy a 9 tan a 1 

 C8. v = sin . ^- = . 



vt/ V ~~~ SiLL A / I 70 o j 7 ^~ " 770 o\ 77 v\~ * 



V \b - x*J dx (b* x 2 ) V( - # ) 



//I cosa;\ <??/ 1 



70. y = tan' /( . j^ = - 



A/ \ J. -j- COS Xj OX A 



^ . ^b + a cos x 



a + b cos x * 



73. 3, = 



dx a + b cos x 



^_. _, i "y 11* i/ i oiij. </ 1 dy \ (a ~ o ) 



/ _. v = tan -< ^ : r . -f" = ^T 



( b + a cos x ) dx a + b cos x 



74. y-.ee-.* 



75. y = tan" 1 



x 2(1 



where 



shew that 



dx 



