After teaching mathematics, calculus and statistics in Canada for so many years, I have learned many useful formulas and shortcuts. For example, we all know the order of addition, subtraction, multiplication and division before addition and subtraction. But for beginners whose mother tongue is English, how to remember these orders easily? So there is the following useful formula: BEDMAS (sounds the same as BED-MATH). BEDMAS, a coined word, clearly tells us the order of mathematical operations.
B: brackets, brackets. As the first letter, this tells us that the first step is to deal with the operation in brackets. Of course, the brackets also contain
It is exponent, exponent and power. The second step is to calculate the power, including the operation of the opposite power, the root sign.
D: it's division, division.
M: multiplication, multiplication.
The next calculation is addition and subtraction.
A: It's addition, addition.
Student: subtraction, subtraction.
Addition and subtraction are sequential operations from left to right, rather than adding first and then subtracting.
Another super useful formula is the formula of trigonometric function. Before talking about this formula, let's introduce the names of three sides in trigonometric function.
In the right triangle shown above, if we choose ∠A as the starting point, then the opposite side is called the opposite side, the longest side is called the hypotenuse, and the bottom side is called the adjacent side. We call these three sides O, H and A for short.
Formulas of trigonometric functions's formula is SOH-CAH-TOA, pronounced so-ca-toe, or sticky hands.
In some engineering majors, I often teach various binary, octal, decimal and hexadecimal conversions and data storage. Today, let's talk about the decimal system commonly used in daily life. Take the length unit as an example, 1 m is 1 m, and 1000 m is 1 km. Do you know the English units of10m and100m? Let's make a list and have a look:
1 km =1000m
1 hm= 100 m
1 dam = 10/0m
1 dm=0. 1 m
1 cm =0.0 1 m
1 mm =0.00 1 m
The way to memorize these units quickly in English is: k ids has d on uts until d ad callsmom.
The first letter of each word represents the corresponding unit. U is the unit, the basic unit. In addition to the length unit, other units can also be substituted, such as weight gram (g). Capacity rise (l).
There is also an interesting version among the people: King Henry Died unexpectedly dug up cola milk.
King Henry accidentally drank chocolate milk and died.
Finally, something related to music. If you are a beginner in guitar, you must remember the six strings of guitar: EADGBE.