This week we learned something about Trigonmetry . I think this is a very interesting one unit , it’s about triangle and angle. Most problems can be reduced to calculations on right-angle triangl
so : tanA = sin A/ cos A
And the teacher taught us one way to remember the letters is to sound them out phonetically, which is ‘SOH-CAH-TOA’ ,it’s very easy to memory and it’s interesting too.But these are built on the premise of knowing the degree of a corner, so when there is no degree of foot, you need to use the Pythagorean theorem.But also have to be careful when doing questions, the United States as I like a joke.
Write is written 9.3 square plus 4.8 square, and the actual time to do, but it is subtraction😂,then get a equal to 8.0.
And then think about it is really should not, a square plus b square is equal to the square of c, the largest c is less than b, how to see should be wrong.
And the correct answer is 10.5, is bigger than 4.8 and 9.3 , and this is a really convenient and swift way to check the answer whether it is right.
And when you hook the theorem, and found that the two sides is a number, this time in order to identify yourself to do the right, you can visualize, the two corners are equal to 45 degrees, if not 45 degrees, then unfortunately you do Wrong; but even 45 degrees is also best to re-calculate it again.
This week we learned that there are about surface area and volume of Spheres,Prisms, Cylinder,Cones and Pyramids.This week, uh, i think it’s a week out of my mind…Because it combines geometric shapes as well as measuring some of the conversion knowledge inside, so it is not particularly easy.But also a small mistake for the week, the specific examples are as follows
So I think in doing this kind of questions, you can draw a map next to, so that both intuitive, and the data and some details can also take into account.And there are plans, I think more convenient for the understanding and calculation of the subject.This question is good, and all the units are ft, but if it is different units have to calculate the first conversion. And if you are not serious, it is possible to use a different unit to do a question, so very troublesome and prone to error.So I just feel very much engaged in the mind, and test your careful degree of the week. If you can not use the knowledge you have learned, then your homework, skills testing and examinations are not good.
So to do more than a few questions to do the title. China has an old saying: reading a hundred times, its meaning from now. So many times to read the subject, you may be able to do the idea of thinking, and pay attention to some small details, which will make you in the subsequent calculation more convenient and accurate.
This week we learned a lot, one of the chapter which taught me a lot , and that is”surface area and Volume of Prisms and cylinders”we learned how to calculate the volume and surface area of prism.I found that the calculation is not as simple as imagined.If you are not careful, you may be wrong with the correct answer. And in the exam, you may be because you do not carefully from more than 90 points to eighty points, here are mistakes what I do.
It is precisely because the question is not serious, will make the triangle with the calculation of the cube, simply forget the triangle area formula is S = 1 / 2ah 😂,and then do the wrong things.So when the next encounter this problem, to learn by analogy, and if not sure, then you can ask the students, students will not or no time to ask the teacher or the Internet Google formula.
I also found that I often made mistakes when making unit conversions. I also analyzed why, when I converted from the large units to small units each time, always like to first converted to m, and then put the answer to the m to fill up, leading to know how to do, the answer is never right
(for example, this is what I did wrong in skills check)
So I think I want to change my habits, or every time the wrong is not worth it
#Tips:Because 1 cm3=1ml 1000ml=1L. So 1cm3=0.001 L
This week I learn about something about ‘ how to write each expression as a power with positive exponents and then as an entire radical.’ When I do the follow question , I calculated it over and over again, but still not the same as the true answer, At that time I was very upset, the draft paper written in a mess. I drank some water, made a deep breath, adjusted my mind, and prepared to finish the rest of the first and then back to recalculate.When the rest of the questions are done and confirmed with the answer, my self-confidence came back, that is a question, how can stop me. So I took a draft paper again, seriously re-copy the title began to do it. This is done very well, the answer is consistent with the true answer. I am very happy and began to step by step with the original written control, found in front of several are the same, to the end of the last when the most deadly mistakes.
（ This is that question that I write it by hand)
So, in the next question, if you encounter the wrong question, and no ideas, you can skip this question, the remaining questions are ready to come back to study the wrong title, so that both save Time, but also self-regulation of the state of mind, not to affect a question of other topics. Especially in the examination, this can also improve efficiency, will not happen a knock knock results lead to insufficient test time, the back of the problem did not do the phenomenon.
The thing that I leran in this week is ‘Simplify.Write the final answer with positive exponents’
When I found that I was wrong, I recorded the correct answer and then began to recalculate on the draft paper.Then I’ll be right, and I’ll take the steps on the draft paper and compare with the steps I had before. Found in the calculation process is wrong to see a a, even if the wrong b as a.
In the future calculation will be more careful to prevent the out of this error. And as far as possible to the last and then about, so as to minimize the occurrence of errors.
Remember: Exponents are lazy ! Only bases are affected by the exponents.
(picture that I drew with hand)
The thing that I leran in this week is ‘how to convert to entire radicals’ , an entire radical of index 3 may be expressed as a mixed radical when the highest perfect cube has been factored out of the entire radical.A mixed radical of index 3 may be expressed as an entire radical by converting the number outside the radical symbol into a radical and then multiplying it by the radicand.
(Pic: I drew it by myself)
Entire to mixed
#3 tell us how many in a group
This also works for other roots (4th,5th,6th,7th…)