Let f (x) = log2 (- x ^ 2-2x + P). If there is no zero point in the definition field of the function, find the value range of the real number P

Let f (x) = log2 (- x ^ 2-2x + P). If there is no zero point in the definition field of the function, find the value range of the real number P

Sorry, there is a mistake, I will correct it and give you a detailed answer

How can FIR filter have zero? I can't see it from a mathematical point of view. Please give me some advice

After Z-transform, the point is substituted into the system function, and the result is 0
For example, H (z) = H (0) + H (1) Z ^ - 1 + H (2) Z ^ - 2, let H (0) = 0, H (1) = 1, H (2) = 1, when z = 1, it is a zero point

When the poles are at the origin and the zeros are z = 0.5 and z = 1.5 respectively, the filtering function of the system is_____ Filter? How to judge,

Low pass filter
Transfer function: H (s) = Kii (s-zj) / II (S-PI)
ZJ is the number of zeros and PI is the number of poles
The pole falls on the origin, pi = 0, and the filtering is linear
When the zero point falls on the positive real axis, ZJ = 0.5, the filtering line falls, ZJ = 1.5, the filtering line falls again
So it's a low-pass filter

How to judge the filter type according to the number and type of zeros and poles of system function
Sorry, it's the position of the sum of numbers on the complex plane

According to the system function to quickly determine the type of filter (1) dead method, using Fourier transform to calculate H (f), in drawing the amplitude frequency characteristic curve, see whether the high frequency part is "pass" (2) using Laplace transform to calculate H (s), and then remember a sentence: what is on the molecule is what! For example: H (s) = as / (BS + C) on the molecule has "..."