小伙伴們，GRE考試大家復(fù)習(xí)的怎么樣了呢？下面是幫考網(wǎng)分享的一些GRE考試數(shù)學(xué)部分的復(fù)習(xí)資料，一起來(lái)看看吧！

GRE數(shù)學(xué)每日一練：

一．Term

A product of coefficients and any number of variables with exponents is called a term. Terms that have the same variables with identical exponents for each variables are called like terms.

Example:

3x,axy,4x2yz are terms. 3x+2 is not term: it is a sum of two terms.

3x2y and 7x2y are like terms since both have the same variables x and y with identical exponents: 2 for x and 1 for y.

Remember:

There cannot be any addition or subtraction in a single term.

Since multiplication is associative, rearrangements of variables does not change a term:3xy is same as 3yx.

3x2y and 7xyx are like terms.

GRE數(shù)學(xué)考點(diǎn)介紹：Conditional

Conditional

Probability of event A conditioned on the fact that event B has happened is called the conditional probability and written as P(AIB).

P(AIB)=Probability Both A and B happens/ Probability B happens.

Example:

A six-sided die with faces from 1 to 6 is rolled twice. What is the probability that the face 5 turned up on first try given that the sum of the two faces is 9?

P(sum of faces is 9)=4/36=1/9.

P(face 5 turns up on the first try and sum is 9)=(1/6)*(1/6)=1/36.

P(face 5 turned up on first try given sum is 9)=(1/36)*(1/9)=1/4

Remember:

If P(AIB)=P(A),then two events A and B are independent, that is occurrence of one does not influence the other

二、概率考點(diǎn)分析

1、等概基本事件組

滿足下列二條性質(zhì)的n個(gè)隨機(jī)事件A1,A2,─ An 被稱為"等概基本事件組"：

⑴ A1,A2,─ An發(fā)生的機(jī)會(huì)相等;

⑵ 在任一實(shí)驗(yàn)中，A1,A2,─ An 中只有一個(gè)發(fā)生。等概基本事件組中的任一隨機(jī)事件Ai(i=1,2, ─,n)稱為"基本事件"。如果事件B是由等概念基本事件組A1,A2,─ An 的m個(gè)基本事件構(gòu)成，則事件B的概率P(B)=m/n,這種討論事件概率的模型稱為"古典概型"。

PS：排列組合結(jié)合概率中的"古典概率"就可以解決幾乎所有的GRE數(shù)學(xué)概率問(wèn)題，但要靈活應(yīng)用，而且很多題目看起來(lái)像概率題實(shí)際上它就是各抽屜原理(6個(gè)球放到5個(gè)抽屜里則至少有一個(gè)抽屜里有兩個(gè)或更多的球)，就讓你比較和1的大小，當(dāng)然是相等。

2、正態(tài)分布

高斯分布(Gaussian)(正態(tài)分布)的概率密度函數(shù)為一鐘型曲線，即a為均值， 為標(biāo)準(zhǔn)方差，曲線關(guān)于x=a的虛線對(duì)稱， 決定了曲線的"胖瘦"。

3、Factoring Polynomial

A general polynomial x2+ax+b can be factored if a=(c+d)and b=c*d for some integers c and d. In that case, x2+ax+b=(x+c)(x+d).

Example:

x2+3x+2=x2+(2+1)x+(2*1)=(x+2)(x+1).

x2-3x+2=x2+(2-1)x+(-2)*(-1)=(x-2)(x-1).

Remember:

Be careful about the signs.

When factoring polynomial,first factor out any common factor.

3、Roots of Polynomial

The number c is a root of a polynomial p(x), if p(c)=0.

An n-th order polynomial has n complex roots.

Example:

2 is a root of polynomial p(x)=x-2,since p(2)=2-2=0.

1 is a root of polynomial p(x)=x2-3x+2,since p(1)=12-3*1+2=0.

Remember:

A polynomial may not have any real root:p(x)=x2+1 does not have any real root, since p(x)>=1 for all real x.

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