ANSWERS 478 



(84) GVx* + Wx - 85 cosh- 1 ~- 



1 r / - x+ 



(35) i|(* + 5) V^ a + 10* - 25 cosh- 1 5 



(86) H(x + 9)Vx*+lOx - 59 cosh' 1 ^J) (87) cosh- 

 ^ ^ ) J 



(38) 3\/.r 2 - 4# - 21 - cosh- 1 2L_? 



(39) ( - 2)V.r 2 -4tf-21 - 25 cosh" 1 



1 . /*> 



(40) |{ (3a? + 4) Vff 2 - 4r - 21 + 97 cosh- 1 



1 . \/6(aJ + 1) 



(41) -7= cosh" 1 - v , ' 



' \/5 V21 



(42) 3V5**+ l(te- 16 - cosh- 1 j 



A/5 V21 



(43) ( + l)Vg^+10-16 - cosh- 



(44) ^{30(0; - 3)V5a; 2 + lOa: - 16 + 221 A/5 cosh' 1 ^J 



XII (pages 181, 182) 

 (1) tan x (2) - cot * (3) 1 tan 3 x (4) - 



(5) - log e sec (ax + b) (6) - log e sin (ax + b) 



& d 



(7) - tan 4 x - tan 2 a? + log,, sec a; 



(8) - tan 5 x - tan 3 x + tan x x 



D o 



(9) - cot 2 x logg sin x (10) - cot 3 x + cot x+ x 



2 o 



(11) 



(12) \ log, {tan i (. - tan- ?)} (13) -L lo& tan (| + | 



(14) 4= log, tan (? - ^ (15) -1= tan- 1 ^ tan f 



y/2 \2 8/ ; 2/3 2 



2\/3 



