Question

a. A = {x | x is a positive integer

less than 10 and 2^x

–1 is an odd

number} write in roster form ​

Answer 1

Please see the attachment

Answer 2

Answer:

Set A = { 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 }

Step-by-step explanation:

We given a Set-Builder form of a Set A.

A = { x | x is positive integer less than 10 and $2^x-1$ is an odd }

We need to write given set in Roaster Form.

Positive integers less than 10 = 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9

Now, applying second condition we get,

we know that $2^x$ is always a even number.

So when 1 is subtracted from $2^x$ gives an odd number.

⇒ Roaster Form of Set A = { 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 }

Therefore, Set A = { 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 }