NCERT Class XI Mathematics - Sets - Solutions
© examsnet.com
Question : 48
Total: 73
Let U be the set of all triangles in a plane. If A is the set of all triangles with at least one angle different from 60°, what is A′?
Solution:
Here U = {x : x is a triangle}
A = {x : x is a triangle and has at least one angle different from 60°}
∴ A′ = U – A = {x : x is a triangle} – {x : x is a triangle and has atleast one angle different from 60°}
= {x : x is a triangle and has all angles equal to 60°}
= Set of all equilateral triangles.
A = {x : x is a triangle and has at least one angle different from 60°}
∴ A′ = U – A = {x : x is a triangle} – {x : x is a triangle and has atleast one angle different from 60°}
= {x : x is a triangle and has all angles equal to 60°}
= Set of all equilateral triangles.
© examsnet.com
Go to Question: