Class 9th math Review Exercise 3 solution english PCTB

Question # 01: Four option are given against each statement. Encircle the correct option.

\((i)\) The set builder form of the set \(\{1,\frac{1}{3} ,\frac{1}{5} ,\frac{1}{7} ,\dotsc \}\) is:

\( a) \quad \) \( \{x\mid x=\frac{1}{n} ,n\in W\} \)

\( b) \quad \) \( \{x\mid x=\frac{1}{2n+1} ,n\in W\}\)

\(c) \quad \) \( \{x\mid x=\frac{1}{n+1} ,n\in W\}\)

\( d) \quad \) \( \{x\mid x=2n+1,n\in W\}\)

Answer: \( b) \; \) \( \{x\mid x=\frac{1}{2n+1} ,n\in W\}\)


Explanation:

Try substituting values of \(n=0,1,2,3,…\) into each option. In option (b), doing this gives the set: \(\{1,\frac{1}{3} ,\frac{1}{5} ,\frac{1}{7} ,\dotsc \}\)

Leave a comment