2. shilling x=y=0, and f (0) = 0; Let y=0, f (x) = 2f (0)+(x+1) (x+1) = (x+1) 2.

3. The squares on both sides of the equation are: (1+tan α 4)/tan α 2 = 23; When tanα=sinα/cosα, we get: sin α 4+cos α 4 = 23 (sin α cos α) 2; Add 2 (sinαcosα) 2 on both sides to get 1 = 25 (sin α cos α) 2. Since α is an acute angle, sin α cos α is a positive value. Therefore, sinα×cosα= 1/5.

We assume that at least two people in 100 are hypocritical. It is easy to know that this assumption is contrary to fact 2 (because any two people may be hypocritical), so the assumption does not hold. It can be seen that at most 100 people are hypocritical, but in fact 1, 1 people are hypocritical, so the number of honest people is 99.