全英文的金融题目,实在做不来啊,有会的帮个忙不?

全英文的金融题目,实在做不来啊,有会的帮个忙不?
Suppose that you write a put contract with a strike price of $40 and an expiration date in three months.The current stock price is $41 and one put option contract is on 100 shares.What have you committed yourself to?How much could you gain or lose?
A company enters into a short futures contract to sell 5,000 bushels of wheat for 250 cents per bushel.The initial margin is $3,000 and the maintenance margin is $2,000.What price change would lead to a margin call?Under what circumstances could $1,500 be withdrawn from the margin account?
A stock index currently stands at 350.The risk-free interest rate is 8% per annum fwith continuous compounding and the dividend yield on the index is 4% per annum.What should the futures price for a four-month contract be?
A one-year long forward contract on a non-dividend-paying stock is entered into when the stock price is $40 and the risk-free rate of interest is 10% per annum with continuous compounding.
最后一道有2问,没写
A one-year long forward contract on a non-dividend-paying stock is entered into when the stock price is $40 and the risk-free rate of interest is 10% per annum with continuous compounding.
What are the forward price and the initial value of the forward contract?
Six months later,the price of the stock is $45 and the risk-free interest rate is still 10%.What are the forward price and the value of the forward contract?
还能更详细点不?我题目看不懂啊,比如第一题write a put换掉呢?long call 之类的呢?

1、第一题题目的意思是,现在在你面前有一份能够以40的价格卖出标的股票的认沽权证,现在标的股票的证券的价格为41元,则说明现在这张权证的价值为0,所以什么都不要动吧,然后没有交易.
如果是long call,则这张权证的价值为100美元,因此买入该认购权证,为了锁定收益,所以每买入一份认购权证合约,就同时抛出100股标的股票（相当于40买入,41卖出）,这样每一张权证的无风险套利收益为100美元
2、第二题题目的意思是初始保证金3000美元,可以购买5000蒲式耳的小麦,小麦单价为2.5美元/蒲式耳,而后他又追加了2000美元的保证金,因此
保证金比例为 3000/（5000*2.5）=24%,所以5000的保证金可以做空的最多5000/0.24=20833.33资金 也就是每蒲式耳小麦低于20833.33/5000=$4.17=417cents不会被强制平仓； 如果要取出$1500则还剩$3500保证金,可以做空3500/0.24=14583.33资金 相当于单价每蒲式耳小麦14583.33/5000=$2.92以下的情况均ok
3、首先更正一下你题目错误的地方,fwith多打了一个f,annum with continuous compounding表示连续复利,我用了360天代替,理论上是用极限做的lim n→正无穷 即(1+12%/n)^n
无风险收益率为8%,风险收益率为4% 总收益率为 12%,问你四个月之后的合约价值为多少or stock index为多少?已知现值求终值.
excel 里面自己输入,=FV(12%/360,120,-350,1)=364.28
4、同上 求一年到期的远期合约价值和现值 价格为=fv(10%/360,360,-40,1)=44.21 合约价值么为0,第二问,如果半年后股票价格为45的话,合约价格=FV(10%/360,180,-45,1)=47.31,合约价值应该总是为0的.应该是格能算额,伐是老确定,因为理论上 远期价格＝即期或现金价格＋持有成本 所以如果没有溢价的话,折现以后价值为0