题目5885 · 数理金融
A one-step CRR binomial tree prices an at-the-money one-year European call at 9.95, while the Black-Scholes value with the same spot, strike, rate and volatility is 8.43. By how much does the coarse tree overprice the option, and what single change to the tree would most directly
打开 →题目5853 · 数学
Determine the radius of convergence of the power series sum_(n=1)^inf (3^n / n) x^n.
打开 →题目2059 · 数学
Near a simple root r with f'(r) != 0, what local rate does Newton's method typically enjoy?
打开 →题目5855 · 数学
For which of the following exponents p does the series sum_(n=1)^inf 1/n^p converge: p = 1/2, p = 1, p = 3/2, p = 2? List all values for which it converges.
打开 →题目3841 · 金融与交易
A trader is long spot and short one futures contract. Initially spot is 100 and futures is 104, so the cash basis is -4. Later the basis changes by 1.5. Ignoring financing, what is the trade's marked-to-market PnL change?
打开 →题目3842 · 金融与交易
A trader is long spot and short one futures contract. Initially spot is 80 and futures is 76, so the cash basis is 4. Later the basis changes by -2. Ignoring financing, what is the trade's marked-to-market PnL change?
打开 →题目3843 · 金融与交易
A trader is long spot and short one futures contract. Initially spot is 52 and futures is 52.8, so the cash basis is -0.8. Later the basis changes by 0.6. Ignoring financing, what is the trade's marked-to-market PnL change?
打开 →题目3844 · 金融与交易
A trader is long spot and short one futures contract. Initially spot is 120 and futures is 123, so the cash basis is -3. Later the basis changes by 2. Ignoring financing, what is the trade's marked-to-market PnL change?
打开 →题目220 · 概率
Let $X_n \sim \text{Binomial}(n, \lambda/n)$ for fixed $\lambda > 0$ and $n > \lambda$.
(a) Write down the characteristic function $\varphi_{X_n}(t) = E[e^{itX_n}]$ in closed form.
(b) Show that $\lim_{n \to \infty} \varphi_{X_n}(t) = e^{\lambda(e^{it} - 1)}$ for every $t \in \
打开 →题目4633 · 数理金融
If the risk-free rate rises while the state payoffs stay the same, which piece of the one-step replicating portfolio is directly affected even before the hedge ratio changes?
打开 →题目4864 · 数理金融
A second-order finite-difference scheme uses Richardson extrapolation E_R = (4E_fine - E_coarse)/3. If E_R=10.6 and E_fine=10.4, what coarse-grid estimate E_coarse is implied?
打开 →题目4865 · 数理金融
A second-order finite-difference scheme uses Richardson extrapolation E_R = (4E_fine - E_coarse)/3. If E_R=2.8 and E_coarse=2.4, what fine-grid estimate E_fine is implied?
打开 →题目2853 · 概率
Let $N_\lambda\sim\mathrm{Poisson}(\lambda)$. Show that
\[
\frac{N_\lambda-\lambda}{\sqrt{\lambda}}\Rightarrow N(0,1)
\quad\text{as }\lambda\to\infty
\]
by working directly with characteristic functions.
打开 →题目2851 · 概率
Let $X_1,X_2,\dots$ be i.i.d. with $P(X_i=1)=P(X_i=-1)=1/2$. Show, using characteristic functions, that
\[
\frac{X_1+\cdots+X_n}{\sqrt n}\Rightarrow N(0,1).
\]
打开 →题目2854 · 概率
Let $X_n\sim\mathrm{Binomial}(n,\lambda/n)$ with fixed $\lambda>0$. Use characteristic functions to show that $X_n\Rightarrow \mathrm{Poisson}(\lambda)$.
打开 →题目4631 · 数理金融
Why does making the binomial time step smaller make the replication route feel closer to continuous Black-Scholes hedging?
打开 →题目4634 · 数理金融
Why does adding more binomial steps usually make backward induction more informative about dynamic hedging rather than less?
打开 →题目3863 · 金融与交易
Why does the cash basis $S-F$ become negative in contango markets?
打开 →题目3864 · 金融与交易
Why does the cash basis $S-F$ become positive in backwardation?
打开 →题目3861 · 金融与交易
Why can a cash-futures hedge still leave risk even if the futures notional matches the cash position perfectly?
打开 →题目3862 · 金融与交易
Why does basis often shrink as a futures contract approaches expiry?
打开 →题目3865 · 金融与交易
Why is basis worth monitoring as its own state variable rather than only watching spot and futures separately?
打开 →题目2069 · 数学
Why is a simple root f'(r) != 0 the standard clean setting for fast Newton convergence?
打开 →题目2485 · 机器学习
Why do exact gradient descent convergence and the normal-equation solution agree for OLS?
打开 →题目5964 · 概率
An urn starts with 1 red and 2 blue balls. Each step a ball is drawn uniformly at random, observed, and returned together with one additional ball of the same color. Let R_n/T_n be the fraction of red balls after n draws. This fraction is a bounded martingale converging to a limi
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