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小伙伴们,GRE考试大家复习的怎么样了呢?下面是帮考网分享的一些GRE考试数学部分的复习资料,一起来看看吧!
GRE数学常见考点:
一、Coefficient
A constant multiplier of a variable is known as coefficient. They are typically represented by letters a,b,c.
Example:
In the expression 3x+5,3 is the coefficient of x.
In the equation 4x+2y=6,4 is the coefficient of x and 2 is the coefficient of y.
In the inequality 2*sin(x)+3>z,2 is the coefficient of the function sin(x).
Remember:
Coefficient cannot change its value.
二、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.
三、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
四、Finding Real Roots
If (x-c) is a factor of the polynomial p(x), then c is a root of p(x).
We can find the real roots of polynomial p(x) by finding all the factors of p(x).
Example:
p(x)=x2+3x+2=(x+1)(x+2). Two real roots of p(x) are -1 and -2.
Remember:
To find if c is a root of p(x), evaluate p(c) and check if p(c)=0.
If x is a common factor of p(x), then zero is a root of p(x).
五:Multiple Times
If probability of an event happening is p, then the probability that the event happens n times in a row is p∧n.
Example:
The probability that a coin toss results in head is 0.5. Then the probability that when the coin is tossed twice, both of them are head is 0.5∧2=0.25.
Probability that a roll of a six-sided die land with face 1 is 1/6. Then the probability that 1 will turn up three times in a row is (1/6)∧3.
Remember:
Note that probability of the event happening does not change from trial to trial.
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