21G. If 

 ;iud 



ALC;I:UI:A. 49 



l-c-af 

 1 



prove that o/ - 2ft w 8 = (- I)- 1 . 



1-x 



217. If 



-, 



ami ^ - - -j = 1 + b t x + bjx?+ ... + b x* + ..., 



1 - x + x* 



prove that a.'- 36^ = 1. 



j 



18. If j = r + ap + a a x* + ... + X -I- ... 



i 



prove that o/ - (r" - 1) ft/ = 1. 



2i:>. The n u convergent to 1 - is equal to the 



1)* convergent to l ^ 2 -h ..- 



.^nation 



prove = * n 



:.-! all 1)10 roota of the equation. Prove that 



V7_V7W7~^TT7 to oo 

 and express the other roots of adratic in the sani. 



w. 4 



