# Maximum value of two parameters function

How can I find the maximum value of that function?

$y(s,t) = \frac{as}{(b + s)} \cdot \frac{t}{(c + t)}$

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Would you care to tell us where is $y$ defined? – Git Gud Jan 13 '13 at 12:14
y is a real number. a,b,c are constants and s,t are real parameters – Iulian Jan 13 '13 at 12:17
I think $y$ is a function, right? If it is, what's its domain? – Git Gud Jan 13 '13 at 12:18
Why can not we put $s=-b$ or $t=-c$ if $a>0?$ – lab bhattacharjee Jan 13 '13 at 12:26
s is in interval (0,7), t - (0.1, 1) and y - (0, 0.1). – Iulian Jan 13 '13 at 12:51