? Next, I will introduce how to use formulas to solve two kinds of problems.
? The first problem is the estimation of irrational numbers with root signs, and the formula is as follows:
Distinguish between squares and cubes,
The first is integer estimation,
The number of estimated digits depends on accuracy,
Don't panic after the knot!
? Explanation: First look at whether the estimated irrational number is a square root or a cube root, then determine the integer part of the estimate, then determine the estimated number of digits according to the accuracy, and finally determine the final result.
The function of the formula is to first clarify the process of doing the problem, and at the same time emphasize the main points that should be paid attention to in each process, so that students can get started doing the problem.
? The second problem is to compare the sizes of two numbers, at least one of which is irrational. The formula is as follows:
There are three estimation ideas:
? Analysis, approximation, square.
? Put it in moderation, big and small,
? Don't panic about the specific process!
? Note: By estimating and comparing the sizes of two numbers, at least one of them is irrational. When it is large, we can estimate the approximate range of irrational numbers through analysis, approximation and leveling, and then compare them in detail.
? To put it bluntly, the process described in the formula is to estimate the size of irrational numbers first and then compare them.
? The meaning of the formula is actually to tell students the process and ideas of solving problems. Teachers can emphasize with examples in specific classes, and supplement some common enlarged or reduced formulas or conclusions, which will help students get started faster.
? I'm Miss Zhao who teaches mathematics. Welcome to pay attention, discuss and forward!