Question

20. Show that 20 shows that Siſi-1). either converges or does not converge.

Answer 1

- (20) D'Alembent Ratio Test: a (tive real numbers. Then lim Mitil ito ai Lut <a:> be sequence of if 11 q let, then I ai converges (11) 9 lit, then Eai divergent. (11) ff l-t, the test fails. Consider & it shule aj = (-1) real For is, 2 ; 9; 7,0 : <a; 7 is sequence of (tive numbers. We can apply Ratio Test. • Scanned with CamScanner

lim ito Aiti ai (+1)(1+1-1) lim i to slin å ina (it) (i+1-1) - ith ů (1-1) = lim ((+1) ito 311-1) = lim í (+ /;) - in a 31/1-4/2) fim (1+ y) 3 (1-16) } +0 - Ź cs Scanned with Scanned with CamScanner

:. l = ☆ <1 L a comenges. å M8 converges Scanned with CamScanner