(E) The integral    equals   ;  it  is  equivalent  to   ,  where
u   =   1   −   ln  t.
(A) Replace u   by  x   in  the given   integral    to  avoid   confusion   in  applying
the Parts   Formula.    To  integrate    ,  let the variable    u   in  the Parts
Formula be  x,  and let dv  be  sec^2 x dx. Then    du  =   dx  and v   =   tan x,  so
(D) The integral    is  equivalent  to   .  Use formula (4) on
the first   integral    and (18)    on  the second.
(D) The integral    is  equivalent  to  .
Use  formula     (17)    on  the     first   integral.   Rewrite     the     second  integral    as 
,   and use (3).
(E) Rewrite:    .
(B) Hint:   Divide, getting .
(D) Letting u   =   sin θ   yields  the integral     .  Use formula (18).