a | c | ||
< | |||
b | d |
a | a+c | c | |||
< | < | ? | |||
b | b+d | d |
a | c | ||
< | /*d (bo d > 0) | ||
b | d |
ad | |
< c /+a | |
b |
ad | ||
a + | < c + a | |
b |
ab + ad | |
< a + c | |
b |
a(b+d) | |
< a + c / : (b+d) (moge bo b+d jest na pewno > 0) | |
b |
a | a+c | ||
< | |||
b | b+d |
a | c | ||
< | /*b | ||
b | d |
bc | ||
a < | / +c | |
d |
bc | ||
a + c < | + c | |
d |
bc + cd | ||
a + c < | ||
d |
c(b+d) | ||
a + c < | /:(b+d) | |
d |
a+c | c | ||
< | |||
b+d | d |