# Continuous prob. distribution

1. Dec 19, 2003

### denian

i really dont know how to ue the Latex. it doesnt work although i try it for many times.

so, im new to this chapter. maybe this question is easy to be solved, but i cant get it.

a continuous random variable X has cumulative distribution as attached.
the question is what is the value of alpha.
i try doing like this but it doesnt give any answer though.

F(-1) = 0 = (alpha)(-1)+(alpha)

what is the working so that i can get the answer.

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Last edited: Dec 19, 2003
2. Dec 19, 2003

### Guybrush Threepwood

blasphemy!!!!

ok, if f(x) is a probability distribution I guess what matters the most is that:
$$\int_D f(x)dx = 1$$
where D is the interval where f is defined (you didn't mentioned it in your question....)

3. Dec 19, 2003

### denian

but that is a cumulative distribution.
i copy the whole thing from the question.

do i need to change it to probability density function first, then continue to work on it.

4. Dec 19, 2003

### Guybrush Threepwood

oh....
then alpha is 1/3 because as I remember $f(\infty) = 1$
and also the function is continuous....

5. Dec 19, 2003

### denian

ok. thank you

Last edited: Dec 19, 2003