How to find the derivative of this function

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
8 replies · 2K views
rishi kesh
Messages
35
Reaction score
3

Homework Statement


How do we find the derivative of function:
y= √[(1-sinx)/(1+sinx)]
This is the exercise problem from my textbook. I have not covered chain rule yet. So please you basic derivative rules to solve it.

Homework Equations


Here is the answer of derivative given in my textbook: secx(tanx-secx)

The Attempt at a Solution


I have tried replacing square root by power of 1/2 but can't reach to the answer.
 
Physics news on Phys.org
rishi kesh said:

Homework Statement


How do we find the derivative of function:
y= √[(1-sinx)/(1+sinx)]
This is the exercise problem from my textbook. I have not covered chain rule yet. So please you basic derivative rules to solve it.

Homework Equations


Here is the answer of derivative given in my textbook: secx(tanx-secx)

The Attempt at a Solution


I have tried replacing square root by power of 1/2 but can't reach to the answer.

Can you see a way to get rid of the square root?
 
  • Like
Likes   Reactions: rishi kesh
PeroK said:
Can you see a way to get rid of the square root?
Hi! Please give me a little bit of intuition about this. I will solve the rest. Thanks in advance !
 
rishi kesh said:
Hi! Please give me a little bit of intuition about this. I will solve the rest. Thanks in advance !
think of manipulating the terms within the square root itself
(1 - sin^2x = cos ^2x)
 
  • Like
Likes   Reactions: rishi kesh
rishi kesh said:
Hi! Please give me a little bit of intuition about this. I will solve the rest. Thanks in advance !
Whenever you have an expression of the form
##\frac{1+x}{1-x}##

you should think about multiplying top and bottom by ##1+x## or ##1-x##
 
  • Like
Likes   Reactions: rishi kesh
PeroK said:
Whenever you have an expression of the form
##\frac{1+x}{1-x}##

you should think about multiplying top and bottom by ##1+x## or ##1-x##
Hi! I am sorry i tried but i couldn't solve it . I would greatly appreciate your help.
 
PeroK said:
Multiply top and bottom by ##1-\sin x## and see what comes out.
Here is a picture of what I've solve. Please tell me if its correct.
 

Attachments

  • 1518543915303-2125212252.jpg
    1518543915303-2125212252.jpg
    30.2 KB · Views: 597
rishi kesh said:
Here is a picture of what I've solve. Please tell me if its correct.
Looks good so far. If you can't use the chain rule, you could look for some standard functions that you know the derivative for.

PS I forgot you could use the quotient rule, although I always think of that as the product rule plus the chain rule.
 
Last edited: