Multiple choice questions 1~5BADDD, 6 ~10ccccab. Fill in the blanks 1 1.i- 1, 12.90 degrees. 13.(0, 1)。 14,.2,3。 15 . f(x)= sinx+sinx cosπ/3+cosx sinπ/3 = sinx+ 1/2 sinx+√3/2 cosx = 3/2 sinx+√3/2 cosx =√3 sin(x+π/6)。 The set of x that gets the minimum value is: {x/x=2kπ-2π/3, k∈z} When x=π/3+2kπ, f(x) gets the maximum value √3 f(x) gets the minimum value: -√3{x/x=π/3+2kπ, k. (1) Because CD//AB, AB is parallel △AEF. Similarly, it can be proved that the CD// plane AEF②. Plane ABCD⊥ Plane BDE⊥ ABCD is square, so DA⊥AB and DA⊥ AEF belong to plane ABCD because of plane ABCD⊥ AEF, so can DA⊥BE ① and AB ⊥ BE2BE ⊥ plane ABCD belong to plane ABCD from ① ②? 438+0)A 1 = s 1 = A+BA2 = S2-s 1 = 4A+B-A-B = 3AD = A2-A 1 = 2A-BS3 = 3a 1+3D = 3。 Sequence sn = 2n2an = sn-sn-1= 4n-2b1= a2 = 6b3 = 54 = b1q2q2 = 9q = 3tn = b1* (1-