Answer 1

The output is the inverted version of the output of AND gate. The symbol for NAND gate is given below

Truth table

I	O	O/P
A	B	Y
0	0	1
0	1	1
1	0	1
1	1	0

 

Answer 2

NAND gate is the combination of AND gate and NOT gate i.e. NAND gate is nothing but it is AND gate with an inverted output.

The Logical statement of NAND gate is if input A is true and B is true then the output if false otherwise
true.

The Boolean equation of NAND gate is `Y = bar(A.B)`

Input	Output
A	B	`Y = bar(A.B)`
0	0	1
0	1	1
1	0	1
1	1	0