A*****e
发帖数: 64 | 1 I am proctoring an exam now. When making the exam, I was trying to simplify
the calculations rather focusing on the conceptual understanding. So, one
of the questions has such a step - solve (x+4)(x-5) = 0. I just saw a
student spent a quite long time to do this :
(x+4)(x-5) = x^2-5x+4x -20 = x^2-x-20 = 0, then x = (1+/-sqrt(1-4*(-20)))/2
= -4 and 5.
This is actually not bad. Very frequently I see some silly mistakes like
exp(-t) + exp(-4t) = exp(-5t). Should I laugh or feel sad? When I first
started teaching years ago, I often felt frustrated and sometimes got upset
with students. Now, I just try to have fun from it, otherwise it is too
much pain. | n**********o
发帖数: 1016 | | y****z
发帖数: 92 | 3 我来讲个故事让你好受些。N年前我当过大一有机化学实验课的TA.有次课是测化合物的
熔点。我告诉学生要测两遍然后取平均值。有个学生的两次数据分别是59度和61度。
我跟她说你把平均值填到实验报告上。她立刻掏出计算器演算。我说你别算了，平均值
应该是60度。她不相信，继续按计算器。当她终于得到了60度，她瞪大眼睛对我说: "
How did you know?"........
Do you feel better now?
simplify
2
upset
【在 A*****e 的大作中提到】
: I am proctoring an exam now. When making the exam, I was trying to simplify
: the calculations rather focusing on the conceptual understanding. So, one
: of the questions has such a step - solve (x+4)(x-5) = 0. I just saw a
: student spent a quite long time to do this :
: (x+4)(x-5) = x^2-5x+4x -20 = x^2-x-20 = 0, then x = (1+/-sqrt(1-4*(-20)))/2
: = -4 and 5.
: This is actually not bad. Very frequently I see some silly mistakes like
: exp(-t) + exp(-4t) = exp(-5t). Should I laugh or feel sad? When I first
: started teaching years ago, I often felt frustrated and sometimes got upset
: with students. Now, I just try to have fun from it, otherwise it is too
| A*****e
发帖数: 64 | 4 Well, just finished grading and saw two silly mistakes:
3(s+10) = s + 13
3(s+10) = 3s + 10
Also, some even cannot tell the difference between numerator and denominator
. These are college junior students we are talking about. WTF! In China
these students would not graduate from elementary school.
【在 y****z 的大作中提到】
: 我来讲个故事让你好受些。N年前我当过大一有机化学实验课的TA.有次课是测化合物的
: 熔点。我告诉学生要测两遍然后取平均值。有个学生的两次数据分别是59度和61度。
: 我跟她说你把平均值填到实验报告上。她立刻掏出计算器演算。我说你别算了，平均值
: 应该是60度。她不相信，继续按计算器。当她终于得到了60度，她瞪大眼睛对我说: "
: How did you know?"........
: Do you feel better now?
:
: simplify
: 2
: upset
|
|
