Fun with logarithms.(a) Simplify the expression ea ln b.

Chapter 2, Problem 13P

(choose chapter or problem)

Get Unlimited Answers
QUESTION:

Problem 13P

Fun with logarithms.

(a) Simplify the expression ea ln b. (That is, write it in a way that doesn’t involve logarithms.)

(b) Assuming that b  ≪ a. prove that ln(a + b) ≈ (ln a) + (b/a). (Hint: Factor out the a from the argument of the logarithm, so that you can apply the approximation of part (d) of the previous problem.)

Problem:

The natural logarithm function, ln, is defined so that eln x = x for any positive number x:

(a) Sketch a graph of the natural logarithm function.

(b) Prove the identities

ln ab = ln a + ln b           and               ln ab = b ln a.

(c) Prove that

(d) Derive the useful approximation

ln(1 + x)  ≈ x,

which is valid when |x| ≪ 1. Use a calculator to check the accuracy of this approximation for x = 0.1 and x = 0.01.

Questions & Answers

QUESTION:

Problem 13P

Fun with logarithms.

(a) Simplify the expression ea ln b. (That is, write it in a way that doesn’t involve logarithms.)

(b) Assuming that b  ≪ a. prove that ln(a + b) ≈ (ln a) + (b/a). (Hint: Factor out the a from the argument of the logarithm, so that you can apply the approximation of part (d) of the previous problem.)

Problem:

The natural logarithm function, ln, is defined so that eln x = x for any positive number x:

(a) Sketch a graph of the natural logarithm function.

(b) Prove the identities

ln ab = ln a + ln b           and               ln ab = b ln a.

(c) Prove that

(d) Derive the useful approximation

ln(1 + x)  ≈ x,

which is valid when |x| ≪ 1. Use a calculator to check the accuracy of this approximation for x = 0.1 and x = 0.01.

ANSWER:

ANSWER:

  1.   The expression can be simplified in this manner,

 

b) The assumption is, b << a.

Step 1:-

So,

                      -----------------------(1)

Now by expanding the 2nd term in the right hand side,  

The higher order terms get smaller and smaller as b is extremely small than a.

So, up to the 1st order,

       --------------------(2)

Add to cart


Study Tools You Might Need

Not The Solution You Need? Search for Your Answer Here:

×

Login

Login or Sign up for access to all of our study tools and educational content!

Forgot password?
Register Now

×

Register

Sign up for access to all content on our site!

Or login if you already have an account

×

Reset password

If you have an active account we’ll send you an e-mail for password recovery

Or login if you have your password back