In order to obtain the partial fractions of an expression, I used the function
Apart to realize it. However the result is shown as Figure 1 which isn't what I want. The result I want is shown in Figure 2. There are three difference between them: 1)there are as few terms in the numerator as possible, 2)the partial fractions are as few as possible, 3)don't appear a negative sign before the first item in parentheses. How to do it? Thanks.
Apart[-((1 + t)/(2 (-1 + t) (-1 + s t)))]