A math problem (high school inequality) Let the plane region represented by inequality x > 0 be o [n] y>0 y

A math problem (high school inequality) Let the plane region represented by inequality x > 0 be o [n] y>0 y

1, f (1) = 3, f (2) = 18, f (n) = (9 / 2) n ^ 2 + (3 / 2) n-3, (n belongs to N + 2), respectively list the expressions of T [n], t [n + 1], and make a difference to get t [n + 1] - t [n] = [(- 81 / 8) (n ^ 2 + 7 / 3N + 1 / 3) (n ^ 2-4n + 16 / 3)] / [2 ^ (n + 1)]. We also know that n ^ 2 + 7 / 3N + 1 / 3 > 0, n ^ 2-4n + 16 / 3 is n + constant for N, that is, t [n

A high school inequality math problem, thanks
Let f (x) be an increasing function defined on (0, positive infinity), set a = {X-2 / X-1 ≤ 0}, B = f (2aX) < f (a + x) a > 0, so that a ∩ B = the value range of real number a of A

1 solution X-2 / X-1 ≤ 0
X-2 ≤ 0 and X-1 > 0
Or X-2 > = 0 and X-1

A mathematical problem about inequality in Senior High School
If the solution set of inequality ax + 1 is less than or equal to B is [- 1,5], find the value of real numbers a and B. It is better to explain the reason in detail

From ax + 1 ≤ B
The results show that - B-1 ≤ ax ≤ B-1
If a > 0, - (B + 1) / a ≤ x ≤ (B-1) / A
Then - (B + 1) / a = - 1, (B-1) / a = 5, the solution is a = - 1 / 2