Option 2:
Let's take two real functions: f(x) = x² g(x) = sin(x)
Point wise multiplication (f×g)(x) = x²×sin(x)
At x = π/2: f(π/2) × g(π/2) = (π/2)² × 1
At x = π: f(π) × g(π) = π² × 0
At x = 3π/2: f(3π/2) × g(3π/2) = (3π/2)² × (-1)
Here, we multiply the values at each corresponding point, making it truly point wise.
Option 1:
If we take a vector v = [1, 2, 3] and try to multiply it with our function f(x) = x², this operation isn't defined as point wise because:
The vector has discrete elements
The function is continuous
They don't have corresponding points to multiply
Option 3:
If we tried to multiply f(x) = x² with a purely imaginary function like h(x) = i×sin(x), the result would be:
(f × h)(x) = i × x² × sin(x) This involves complex numbers and isn't a real function multiplication
Option 4:
If we multiply f(x) = x² by a scalar k = 2:
(k × f)(x) = 2x² This is just scaling the function, not point wise multiplication as we're not multiplying two functions at each point.
Hence, Option 2 is Correct.