How to get the multiple-choice questions right has a great chance. Multiple choice questions are very skillful. First of all, we should make full use of the selectivity of multiple choice questions. It is a good way to introduce special values. Secondly, you can look at the relevance of ABCD and try to choose the one that can highly summarize other options. For example, part of the BCD option can be spelled as a, of course, choose a!
Three short and one long choose long, three long and one short choose short, two long and two short choose B, and Qi C is invincible. Choose c for the same length and b for the same short length. If it's an image problem, which is more likely to get B or C!
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 unless you are more than 90% sure.
This series of methods often give some conditions, such as a greater than or equal to 0 and less than or equal to 1. B is greater than or equal to 1 and less than or equal to 2. Considering some special circumstances, it may be complicated for you to find some formulas for combining ab. But if it is a multiple-choice question, you can try a=0.5 and b= 1.5. There is also a formula that can bring the answers in the options to the questions for calculation. Backward method!
Interval method, also known as exclusion method, relies on roughly calculated data or guesses some data. For example, how many angles are given to a topic, 30 and 90. Obviously, the answer must be 90 30 degrees, 120 plus or minus 30 degrees. Or some answers related to 30, 60 or 90 degrees.
Coordinate method, if you can't find ideas in some graphic problems, you can use the proportional method first, and then use the coordinate method. You can directly find the coordinates of two points, regardless of any trigonometric function, and directly bring in the high school function to find the angle (cos formula), vertical formula, length formula and tangent formula. Go straight to Huanglong without looking for an angle to do anything troublesome.
Proportional method, this method is very simple and rogue. If you encounter graphics problems, mark the known first, measure the unknown with a protractor, and then it is time to witness the miracle! Measure the proportional relationship between two solid lines with a ruler, and then estimate the length of a known side approximately by the ratio of that side.
Function method, this is to convert some calculations into functions, first bring in the answers, then shift the terms, turn one side of the equation into zero, and then you can roughly draw the expression of the function to see if there is a unique focus with zero, so that you can roughly judge the answers or find the answers closest to zero!
Empirical method: it is also used in sorting or conventional topics. First, for example, find the triangle area. Look at the answers A: 12, B: 13, C: 6, D: 1 1. First, 12, 13, 1 1 are obviously the wrong answers. Secondly, there must be a trap of forgetting to divide the triangle area by 2, so the correct rate of C's answer is high. There are some answers, and the first few are repeated, just like the picture below, so we won't just choose to repeat more answers! 1 2 There are two duplicate answers, and C and D are the most likely.
If, really can't find any method, then look at the answer, there are * * * common divisors generally have the correct answer. Generally, those answers will not have similar answers to the other three, but they are generally wrong. It can be ruled out directly, and finding the answer is actually finding the difference. Look through the author's thoughts, consider what trap the topic wants to set, and eliminate some irrelevant answers.