Write the negation of the following statements.

Question:
(i) Both the diagonals of a rectangle have the same length.
(ii) 7 is rational.

Solution:
(i) This statement says that in a rectangle, both the diagonals have the same length.
This means that if you take any rectangle, then both the diagonals have the same length.
The negation of this statement is:
It is false that both the diagonals in a rectangle have the same length.
This means the statement
There is atleast one rectangle whose both diagonals do not have the same length.

(ii) The negation of the statement in (ii) may also be written as:
 It is not the case that 7 is rational.
 This can also be rewritten as 7 is not rational.