Mathematics problems of compulsory five in senior one Let the opposite sides of the inner angles a, B and C of the acute triangle ABC be a, B and C respectively, and a = 2bsina (1) Find the size of ∠ B (2) If a = 3 √ 3, C = 5, find B If I'm not wrong, the first question B is 30 degrees?

Mathematics problems of compulsory five in senior one Let the opposite sides of the inner angles a, B and C of the acute triangle ABC be a, B and C respectively, and a = 2bsina (1) Find the size of ∠ B (2) If a = 3 √ 3, C = 5, find B If I'm not wrong, the first question B is 30 degrees?

Upstairs SINB = 1 / 2, isn't B 30?. second question B = root 7? (note that acute triangle B = 30 degrees)

The solution set of known inequality (AX square + BX + C) + (x + D) > 0 is {x | X

The known inequality is (AX ^ 2 + BX + C) * (x + D) > 0, and the solution set is {x | X

Senior one compulsory five series
It is known that the sum of the first n terms of the sequence {an} is SN
If Sn = [(1) ^ n + 1] xn, find A5 + A6 and an
If Sn = (3 ^ n) + 2n + 1, find an

If Sn = [(1) ^ n + 1] xn, Sn = 2n, n = 1, an = 2. N > = 2, an = sn-sn-1 = 2, so an = 2
If Sn = (3 ^ n) + 2n + 1, when n = 1, an = 6, when n > = 2, an = sn-sn-1 = 2 * 3 ^ (n-1) + 2
Are you sure it is (1) ^ n