Double Differentiation of (e^-x)(1-x)^1/2: Correct Solutions

  • Thread starter Thread starter cabellos
  • Start date Start date
Click For Summary
The discussion focuses on the double differentiation of the function (e^-x)((1-x)^1/2). The first derivative is confirmed to be correct, but the second derivative needs clarification and simplification. There is confusion regarding the expression '(1/2(1-x)^3/2)', which should be clearly defined to avoid misinterpretation. Participants suggest factoring out (1-x) from the first derivative to simplify the second differentiation process. Overall, the emphasis is on ensuring clarity and accuracy in the differentiation steps.
cabellos
Messages
76
Reaction score
1
I have to differentiate (e^-x) ((1-x)^1/2) twice:

The first time i differentiate i get

(-e^-x) ((1-x)^1/2) + (e^-x) ((1-x)^-1/2) (-1/2)

then differentiating this i get

[(e^-x) ((1-x)^1/2)] - [(e^-x) ((1-x)^-1/2) (-1/2)] + [(-1/2e^-x) (1/2(1-x)^3/2) + ((1-x)^-1/2) (1/2e^-x)]

are these correct?

thankyou for checking
 
Physics news on Phys.org
If you want someone to check something for details, you should make sure you've shown what you want checked clearly and unambiguously. What does this mean '(1/2(1-x)^3/2)'? Is it (1/2)*(1-x)^(3/2)), or ((1/(2(1-x))^3)/2) etc etc. That said there should be terms with (1-x) to the power of 1/2, -1/2 and -3/2 (not 3/2). Other than that ok, I think.
 
First derivative is OK. Before differentiating for the second time please write the first derivative nicer by taking (1-x) out of the first term and do some adding. I am sure that simplification will result.
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

Similar threads

  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 5 ·
Replies
5
Views
2K
Replies
4
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 7 ·
Replies
7
Views
1K
  • · Replies 6 ·
Replies
6
Views
1K