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bio website kelliesmith.info
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visits member for 2 years
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8h
comment what does $p(-1) = 0$ mean?
is there a function p(x) defined anywhere else in the question?
Jan
26
awarded  Popular Question
Jan
24
answered find a vector with certain magnitude that is parallel to another vector
Jan
24
comment Proving that an infinite sum of irrationals is irrational
As currently phrased, the 'an' in your question looks like you are asking 'is every sum of irrationals irrational'. Answer no as Pp has shown. If you are asking about a particular set of irrationals then please say what they are.
Jan
24
comment An Elementary Convergence Problem in Probability
Do the density functions integrate to 0? Do they need to be delta functions to integrate to 1?
Jan
3
comment what $A$ makes $X$ in $\dot{X}=-AX$ converge?
Yes, because the matrix X can be treated as n separate n x 1 vectors
Jan
3
comment what $A$ makes $X$ in $\dot{X}=-AX$ converge?
Also en.wikipedia.org/wiki/…
Dec
24
answered Can Point inside quad be determined with angles alone?
Dec
24
comment Can Point inside quad be determined with angles alone?
?? typo ∠CGB+∠BGE+∠EGD=180
Dec
24
comment How many 5-character passwords can be made from 5 characters with joins?
@sashasami Thank you
Dec
24
revised How many 5-character passwords can be made from 5 characters with joins?
added 2 characters in body
Dec
24
asked How many 5-character passwords can be made from 5 characters with joins?
Oct
3
revised What is probability that a sample covers all classes?
Corrected formula, used same notation as possible duplicate
Oct
3
comment What is probability that a sample covers all classes?
Is this a duplicate of math.stackexchange.com/questions/32800/… ?
Oct
3
revised What is probability that a sample covers all classes?
added 40 characters in body
Oct
3
asked What is probability that a sample covers all classes?
Jul
21
comment Using integral definition to solve this integral
For every partition P there is a partition P' where P' has fixed delta equal to the smallest $t_i - t_{i-1}$ in P. Since the function is decreasing, s(f; P) < s(f; P'), and so $$\sup_P s(f;P) \le \sup_{P'} s(f;P')$$ But P' is just a (specialised) partition, so $$\sup_{P'} s(f;P) \le \sup_{P} s(f;P)$$ So $$\sup_P s(f;P) = \sup_{P'} s(f;P')$$ and from there you can use Mhenni Benghorbal
Jul
11
comment Probabilty with profit question.
It depends what you mean by "profitable". Average or expected profit is the sum of (probability * profit) e.g. for first table 1/3 * 350 + 1/6 * 350 - 1/6 * 100 - 1/3 * 100. Maximum profit is just 350 for the first table etc
Jul
11
comment How do you find the equation of this straight line?
And note that you can get $b$ in terms of $a$
Jul
11
comment How do you find the equation of this straight line?
Use implicit differentiation to get m = dy/dx. Then (for tangent) find line with slope m, passing through whatever point you've been given. For normal, find line with slope -1/m passing through the point.