# All Questions

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### convex and concave regions

I was doing this question and it quoted that "Given that the region OCB is convex..." but surely that region is concave as a basic way is that a line between two points can be drawn under the curve. ...
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### Determine for $f(x)=x^3-x+3$ a $n \in \Bbb Z$, sucht that $f(x)=0$, for a $x\ \in [n,n+1]$. [closed]

Determine for $f(x)=x^3-x+3$ a $n \in \Bbb Z$, sucht that $f(x)=0$, for a $x\ \in [n,n+1]$. I'm not sure how to tackle this problem for a $x\ \in [n,n+1]$. I was thinking about using the intermediate ...
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### Calculating Covariance when three coins are flipped [closed]

Three fair coins are flipped. Let x be the number of heads. Let y equal to 1 if all coins land the same outcome I.e hhh or ttt, and 0 if otherwise. Calculate Cov(X,Y)
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### what does ^-1 mean?

Im kind of frustrated when I see the experession of (something)^-1 and its not really clear from context that it means 1 over something or the inverse of somethings. This issue shows up frequently in ...
488 views

### How do I change the X-step on the TI-84 Plus?

I am trying to create a vertical line in my calculator, but it needs to be restricted to a certain height. I have an equation with a very high slope and I need to restrict its domain to hundredths. I ...
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### Prove an equation has exactly two real roots [closed]

If i want to prove and equation has exactly two real roots, how would i do so? What theorem would i use, Rolle's or Bolzano's or something else?
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### Prove that, If $p > 0$ and $\Bbb{E}(|X|^p )< \infty$, then $x^p \Bbb{P}(\{ |X|>x\}) \sim o(1)$ as $x \to \infty$

Prove that, If $p > 0$ and $\Bbb{E}(|X|^p )< \infty$, then $x^p \Bbb{P}(\{ |X|>x\}) \sim o(1)$ as $x \to \infty$ I tried to solve this question in class but I ended up with the difficult ...
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### Find the Polar equation of the curve made of all points P such that the distance from O to P equals the distance from A to B.

Crude picture but its the best i could do. Do not even know where to start with this particular problem. I'm almost positive it deals with cycloids but that is about it.
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### Let $w$ denote cube root of unity which is not equal to 1. Then the number of distinct element in the set {$(1+w+w^2+…+w^n)^m : m,n=1,2,3,..$} [closed]

I know it follows part cycle mod 3 but I don't understand how to find different element in set, do I have to think of all possible values in the set?