Shahab
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 7h comment If $f$ is odd how does this imply that $f$ is symmetric about the origin in polar coordinates? I think the question is wrong. As per the criteria here(pg 2), the curve is going to be symmetrical about the y-axis: saylor.org/site/wp-content/uploads/2011/04/… 10h comment If $f$ is odd how does this imply that $f$ is symmetric about the origin in polar coordinates? Yeah I know. I deleted my comment. What you want is $(-R,\theta)$ or $(R,\theta+\pi)$ 10h comment If $f$ is odd how does this imply that $f$ is symmetric about the origin in polar coordinates? $r=\theta$ is not the graph of the function $f(x)=x$ which is the identity function. 10h comment If $f$ is odd how does this imply that $f$ is symmetric about the origin in polar coordinates? You are not plotting the identity function in polar coordinates properly. It will not be $r=\theta$ but $\cos\theta=\sin\theta$. 10h revised Please explain how to prove its one one onto edited title 10h comment How many elements are in the Cartesian product You can try to figure out what is the minimum and maximum number in $A$ for starters. 10h comment How many elements are in the Cartesian product How many elements are there in $A$? In $B$? 11h reviewed Reject How does the these steps came? 11h reviewed Approve List the elements of the set s= 11h reviewed Approve Intuition for least square regression line involving joint distribution 11h comment Please explain how to prove its one one onto Do you wish to prove the existence of a one to one function? 11h reviewed Approve Please explain how to prove its one one onto 11h comment Choose unique numbers from different sets Are the sets finite? 2d comment How do I prove this using mathematical induction? There are a bunch of non inductive proofs here: math.stackexchange.com/questions/7757/… 2d comment How do I prove this using mathematical induction? Here is a quick proof without induction: In a collection of $n$ people one counts the number of ways of choosing a committee with a chairperson. One way to count is to first choose the committee then the chairperson (LHS) and another way is to choose the chairperson and then the committee (RHS). 2d comment Help with Relations and Functions? Don't you mean $\mathbb Z$ instead of $\mathbb Z +12$? 2d comment If the set of all polynomials is infinite-dimensional, then why is the set of all functions on [a,b] also infinite-dimensional? Once you have proved that a subspace is infinite dimensional it directly follows that the original vector space is infinite dimensional as well. You can prove this in general using the contrapositive form. 2d comment If the set of all polynomials is infinite-dimensional, then why is the set of all functions on [a,b] also infinite-dimensional? Wouldn't the polynomials interpreted as functions restricted to $[a,b]$ be an infinite dimensional subspace of $U[a,b]$? Oct 5 reviewed Approve Formula to Move the object in Circular Path Oct 5 comment How did this result come about? The rule $\sum_{k=l}^{\lfloor n/2\rfloor}\binom{n}{2k}\binom{k}{l}=\frac{n}{2}\frac{(n-l-1)!2^{n-2l}}{l!(n-2l)‌​!}$ may be helpful.