Question
For any two sets, prove that:
$\text{A}\cup(\text{A}\cap\text{B})=\text{A}.$

Answer

$\text{A}\cup(\text{A}\cap\text{B})=(\text{A}\cup\text{A})\cap(\text{A}\cup\text{B})$ $[\because$ union $\cup$ is distributive over intersection $\cap]$
$=\text{A}\cap(\text{A}\cup\text{B})$ $[\because\text{A}\cup\text{A}=\text{A}]$
$=\text{A}[\because\text{A}\subset(\text{A}\cup\text{B}),$ as union of two sets is bigger then each of the individual sets$]$
Hence, $\text{A}\cup(\text{A}\cap\text{B})=\text{A}$ Proved.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

Solve the following equations:
$5\cos^{2}\text{x}+7\sin^{2}\text{x}-6=0$
How many words each of 3 vowels and 2 consonants can be formed from the letters of the word INVOLUTE?

The sum of 4th and 8th terms of an A.P. is 24 and the sum of the 6th and 10th terms is 34. Find the first term and the common difference of the A.P.

The number of bacteria in a certain culture doubles every hour. If there were 30 bacteria present in the culture originally, how many bacteria will be present at the end of 2nd hour, 4th hour and nth hour?
The function f : X → R is defined by f(x) = x+ 1, where X = {-1, 0, 3, 9, 7}.
Find the point in yz-plane which is equidistant from the points A(3, 2, -1), B(1, -1, 0) and C(2, 1, 2).
Differentiate the following function with respect to $(\text{x})$:

$\frac{(\text{x}+5)(\text{2x}^2-1)}{\text{x}}$

A person writes a letter to four of his friends. He asks each one of them to copy the letter and mail to four different persons with instruction that they move the chain similarly. Assuming that the chain is not broken and that it costs 50 paise to mail one letter. Find the amount spent on the postage when 8th set of letter is mailed.
Show that the tangent of an angle between the lines $\frac{\text{x}}{\text{a}}+\frac{\text{y}}{\text{b}}=1$ and $\frac{\text{x}}{\text{a}}-\frac{\text{y}}{\text{b}}=1$ is $\frac{2\text{ab}}{\text{a}^2-\text{b}^2}.$
A(5, 3), B(3, -2) are two fixed points; find the equation to the locus of a point P which moves so that the area of the triangle PAB is 9 units.