Class 9th math 3.2 solution english PCTB

Question 2: Let, \(U=\{x:x\text{ is an integer and }0<x\leq150\}\), \(G=\{x:x=2^m\text{ for integer m and }0\leq m\leq 12 \}\) and \(H=\{x:x\text{ is a square}\}\).

\((i)\) \(\;\) List all elements of sets \(G\) and \(H\) in tabular form

Solution:

\(G=\{1,2,4,8,16,32,64,128\}\)

\(H=\{1,4,9,16,25,36,49,64,81,100,121,144\}\)


Explanation:

\(G=\{x:x=2^m\text{ for integer m and }0\leq m\leq 12 \}\)

We’re finding all powers of \(2\) such that the result is less than or equal to \(150\) because our universal set is upto \(150\).

\(2^0=1,\:\)\(2^1=2,\;\)\(2^2=4,\;\)\(2^3=8,\;\)\(2^4=16,\;\)\(2^5=32,\;\)\(2^6=64,\;\)\(2^7=128\;\)

\(H=\{x:x\text{ is a square}\}\).

We want all perfect squares from 1 to 150.

\(1^2=1,\;\)\(2^2=4,\;\)\(3^2=9,\;\)\(4^2=16,\;\)\(5^2=25,\;\)\(6^2=36,\;\)\(7^2=49,\;\)\(8^2=64,\;\)\(9^2=81,\;\)\(10^2=100,\;\)\(11^2=121,\;\)\(12^2=144\;\)

Tips for Students:

  • Always look at the condition \(x \leq 150\) to know when to stop.
  • Use tables or calculators to compute powers and squares.

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