-
Consider the following statements
(1) If S1 and S2 are linear, then S is linear
(2) If S1 and S2 are nonlinear, then S is nonlinear
(3) If S1 and S2 are causal, then S is causal
(4) If S1 and S2 are time invariant, then S is time invariant Of these statements true statements are
-
- 1, 2, 3
- 2, 3, 4
- 1, 3, 4
- all of these
Correct Option: C
Only statement (b) is false. For example
S1 : y[n] = x[n] + b
S2 : y[n] = x[n] – b, where b ≠ 0
S{x[n]} = S2 {S1 {x[n]}} = S2 {x [n] + b} = x[n]
Hence S is linear.
