Products in Fraction: Bigger with Sub/Super Scripts

[rapid1]

Basically i have this code, obviously the fraction is in display maths, but i want BIG products too, with sub/super scripts above and below rather than next to it. Thanks

$$
pr(X=k)=\mu\frac{\prod^{k-1}_{i=1}\{1-\mu+(i-1)\theta\}}{\prod^{k}_{i=1}\{1+(i-1)\theta\}}, \quad \mbox{for k$\geq$ 1,}
$$

 

[pedja]

Basically i have this code, obviously the fraction is in display maths, but i want BIG products too, with sub/super scripts above and below rather than next to it. Thanks

$$
pr(X=k)=\mu\frac{\prod^{k-1}_{i=1}\{1-\mu+(i-1)\theta\}}{\prod^{k}_{i=1}\{1+(i-1)\theta\}}, \quad \mbox{for k$\geq$ 1,}
$$

type \displaystyle in front of \prod$$
pr(X=k)=\mu\frac{\displaystyle\prod^{k-1}_{i=1}\{1-\mu+(i-1)\theta\}}{\displaystyle\prod^{k}_{i=1}\{1+(i-1)\theta\}}, \quad \mbox{for k$\geq$ 1,}$$

 

[Evgeny.Makarov]

There are two ways to place limits above and below an operator. First, this is the default for big operators in display style. Here, the fraction is in display style, but the nominator and denominator are in text style. You can activate display style using \displaystyle in the nominator and denominator or by using \dfrac instead of \frac. Second, without changing the style, you can put the limits above/below the operator by saying \prod\limits. Conversely, in display style limits can be put next to the operator by saying \prod\nolimits.

See also p. 144 of The TeXbook.

 

[rapid1]

And it's as simple as that :p Thanks very much!