It is very important to get more points in the college entrance examination. If we encounter multiple-choice questions that we can't, we can also choose to get them! For example, someone summed up the skills of mathematics in the college entrance examination!
1. Special value test method
For a general mathematical problem, we can specialize the problem in the process of solving it, and use the principle that the problem does not hold in special circumstances and does not hold in general circumstances to achieve the purpose of removing the false and retaining the true.
Example: the three vertices of △ABC are on the ellipse 4x2+5y2=6, where the two points A and B are symmetrical about the origin O. Let the slope of the straight line AC be k 1 and the slope of the straight line BC be k2, then the value of k 1k2 is
A.-5/4 B.-4/5 C.4/5 D.2√5/5
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Analysis: Because the value of k 1k2 is required, we can know from the stem that the value of k 1k2 is a fixed value. There is no specific location of a, b and c, because it is a multiple-choice question, so there is no need to solve it. Through simple drawing, we can get the most easily calculated value. We might as well make A and B two vertices on the long axis of the ellipse and C one vertex on the short axis of the ellipse, so we can directly confirm the intersection point and simplify the problem, so we choose B.
2. Extreme value test method
Analyze the problem to be studied to the extreme state, so that the causal relationship becomes more obvious, thus achieving the purpose of solving the problem quickly. Extreme value is mainly used to find extreme value, range and analytic geometry. Many problems with complicated calculation steps and large amount of calculation can be solved instantly once extreme value analysis is adopted.
3. Exclusion method
Using the known conditions and the information provided by the selection branch, three wrong answers are eliminated from the four options, so as to achieve the purpose of correct selection. This is a common method, especially when the answer is a fixed value or has a numerical range, special points can be used instead of verification to exclude it.
4. Number-shape combination method
According to the conditions of the topic, make a graph or image that conforms to the meaning of the topic, and get the answer through simple reasoning or calculation with the help of the intuition of the graph or image. The advantage of the combination of numbers and shapes is intuitive, and you can even measure the result directly with a square.
5. Recursive induction
Through the conditional reasoning of the topic, we can find the law and sum up the correct answer.
6. Forward cracking method
Using mathematical theorems, formulas, rules, definitions and meanings, the method of obtaining results through direct calculus and reasoning.
Example: The bank plans to invest part of its funds in Project M and Project N for one year, of which 40% will be invested in Project M, 60% in Project N, and the annual income of Project M will be 65,438+00%, and the annual income of Project N will be 35%. At the end of the year, banks must withdraw funds and pay them to depositors at a certain rebate rate. In order to make the annual profit of the bank not less than 10% and not more than 15% of the total investment of M and N, the minimum rebate rate of depositors is ()
A.5% B. 10%
Analysis: Let * * have funds as α and the depositor's rebate rate χ, and we can get 0.1α≤ 0./kloc-0 /× 0.4α+0.35× 0.6α-χ α≤ 0.15α from the meaning of the question.
The solution is 0. 1≤χ≤0. 15, so choose B.
7. Reverse verification method (answer verification method)
Substitute the selected branch into the stem for verification, so as to deny the wrong selected branch and get the correct method of selecting branch.
Example: Let both sets m and n be positive integer sets N*, and map f:M→ map element n in set m to element 2n+n in set n, then the original image of image 37 is () under map f. ..
a3 b . 4 c . 5d . 6
8. If it is difficult, it is illegal.
When it is difficult to solve the problem from the front, we can find a qualified conclusion step by step from the choice of expenditure, or draw a conclusion from the opposite side.
9. Characteristic analysis method
Analyze the characteristics of topic setting and branch selection, find the law and summarize the correct judgment method.
For example, 256- 1 may be divisible by two numbers between 120 and 130, which are:
A. 123， 125 B. 125， 127 C. 127， 129 D. 125， 127
Analysis: The square difference formula of junior middle school is from 256-1= (228+1) (228-1) = (228+1) (21).
10. Appraisal selection method
Some problems cannot (or are not necessary) be accurately calculated and judged due to the limitation of subject conditions. At this time, we can only get the correct judgment method from the surface by means of estimation, observation, analysis, comparison and calculation.
Summary: Multiple-choice questions in college entrance examination are generally easy or intermediate, while individual questions are more difficult. Most of the answers can be quickly selected by special methods. Such as valuation selection method, special value test method, forward deduction method, combination of numbers and shapes, feature analysis method and reverse deduction verification method are all commonly used solutions. Special attention should be paid when solving problems: only one of the four choice branches of multiple-choice questions is correct, so the comparison of choice branches is very important when solving problems, which is the basic premise of quick choice and correct answer.
1. In the multiple-choice math questions in the college entrance examination, we can first exclude two certain wrong options by exclusion, and then choose the right one from the other two options according to our own calculation and understanding of the stem.
2. There is also a special skill in the multiple-choice questions of college entrance examination mathematics. In other words, if you have made three multiple-choice questions in a row, and all of them are the same choice, then you need to check these three multiple-choice questions again, because it is impossible to have the same answer for three multiple-choice questions in a row.
3. In the math multiple-choice questions of the college entrance examination, it can also be verified by data calculation. For the options you are not sure about, you can verify the data in other options after exclusion. If the data has a certain deviation, the option is wrong.
4. There may be some graphic questions in the math multiple-choice questions. If you can't find a solution to this kind of problem, you can use some coordinate knowledge points instead. We don't have to think from the perspective of graphics, but we can think about graphics from other angles and maybe find a suitable way of thinking.
There are some calculation questions in the multiple-choice questions of the college entrance examination, which will require you to get some specific angle data. You can use the relevant data knowledge given in the title, and sometimes you can get some data related to options. For example, if the angle given in the stem is 60 degrees, you can get some 90 degrees or 120 degrees in the options, which is a multiple of 60 degrees.
Mongolian body is also a science. I am a senior three student, and the success rate of math puzzles is over 70%. First of all, make it clear that the problem can't be pure, and you must have the effect of seeing the problem after reading it. If you can't do it after reading the question, look at the options first, some can be excluded, and then analyze according to the conditions of the question, and some options may be excluded, which will be much easier.
If you can't rule out any of them, then consider the option. If there is an answer about extracurricular (which rarely appears in class), it is probably that. If the number of options is 4, usually the second largest option is the correct option. Looking at the options alone, there are generally more BD and less A. One more thing, don't change it after you choose it unless you are more than 90% sure.
Math puzzle skills ii
As far as I know, the first question in mathematics is generally not A; The last question will not be a; The answers to multiple-choice questions are evenly distributed; Fill in the blanks not only with 0 or1; If the answer has a root sign, don't choose; If the answer is 1, select; When all three answers are yes, choose the right one; When one is positive x and the other is negative x, choose one of them; The topic looks simple, so the answer is complicated, and vice versa; What to choose in the previous question, what to choose in this question, if there are three identical ones in succession, it is not; When none of the above is practical, choose B.
In the calculation, you should write an answer first. If the number of options is 4, usually the second largest option is the correct option. Looking at the options alone, there are generally more BD and less A. One more thing, don't change it after you choose it unless you are more than 90% sure. Fill in the blanks according to the selection of related graphics can take special values.
You can't make a big problem, you can't use the conclusions you ask, and you can't deduce the conclusions you can think of according to the conditions. Usually you have points. If you are lucky, you can get more than half of 1. Fill in the blanks carefully, jump without thinking for 2 minutes, don't write the most possible answer, the chance of getting it right is not small.
2 mathematical puzzle solving skills code
Mathematical puzzle solving skill code
1. If the answer has a root symbol, please do not select it.
2. If the answer is 1, please select.
3. When all three answers are yes, choose the right one.
4. When one is positive X and the other is negative X, choose one of them.
If the question looks simple, then the answer is complex, and vice versa.
6. If you choose the previous question and this question, it is not suitable to do this article if there are three identical ones in a row.
7. A good answer depends on your eyes.
8. when none of the above is practical, choose B.
Mathematics is reexamined from easy to difficult.
Fill in the blanks: be careful again. In mathematics subjective questions, fill-in-the-blank questions are not like the big questions behind, and need specific problem-solving steps. It only requires candidates to give a final answer. This requires candidates to be more careful in answering questions and solve problems step by step.
Big problem: the steps need to be clear. In the process of correcting big questions (calculation questions, proof questions), the main points and conclusions of the process are generally given separately. Therefore, candidates should write down the steps clearly when answering questions, so that they can not only get the step marks, but also help their later investigation. Otherwise, it's like filling in the blanks. If the answer is wrong, there is no score.
Self: Positioning needs rationality In recent years, there have been some strange phenomena in the college entrance examination, that is, some students usually perform well, but their papers just can't get up. This is mainly because there is something wrong with students' own positioning. Because these candidates spend too much time on difficult questions, the probability of making mistakes on easy questions is greatly increased. In fact, the proportion of difficult questions in the exam is only 20%. Therefore, candidates should not have the irrational idea that "the question must be chewed up" when answering questions. As long as you get all the easy questions honestly, the scores in the exam will not be very low.
Answer: Be bold again. If you are not sure, you'd better not erase the original answer. Both methods can be written on the test paper. The marking teacher will generally give points according to the method of high scores.
3 college entrance examination mathematics multiple choice trick
Quantity principle
Ideal state: 15 questions, each with 5 options, and each option appears 3 times on average: A, B, C, D and E. Answer arrangement: three three three three three three.
Actual status: Each option is in the range of 2-4.
Option arrangement: 3, 3, 3, 2, 4 (this state is slightly more) or 3, 2, 4, 2, 4. That is, there are two options and four options.
Three different principles
That is, three questions in a row will not have the same answer in a row.
The alphabetical order of ABCDE will not appear in the answer arrangement.
doctrine of the mean
That is, the "intermediate quantity" option is preferred for numerical values, and BCD is preferred for options. On the same topic, give priority to the "intermediate quantity" of the value and then consider the option BCD. (If the value corresponding to option E is intermediate, the numerical value should be considered first. )
Options such as "None of the above results are correct" will not be considered.
Starting with extracting the given information, the wrong options are eliminated through option features.
The basic characteristics of these options are as follows:
Single-valued and multi-valued (such as even power, absolute value, symmetry and other results with multi-values)
Positive and negative values (excluding negative values according to the propaganda of P 12/25 before the exam)
There is zero and there is no zero.
The beginning and end of the interval (see if extreme cases can be equal)
Positive infinity and negative infinity (through limit consideration)
Integer and Decimal (Fraction)
Prime number and composite number
Greater than and less than
Separable and inseparable
Signed and unsigned (such as root sign, plus sign, etc.). )
The minority obeys the majority principle.
That is to say, look at the characteristics of options, and options with the same characteristics have priority.
Simplify complex expressions
Generally speaking, the options are 1, 2,0,-1 and -2.
Without positioning before and after, you won't have to guess all the questions in a row.
Observe the completed options, and if there are few options, write all these questions as this option.
The answer often appears in several reciprocal options (probability questions) that add up to one.