Algebra in trigonometric identities

(a+- b)2=a2+-2ab+b2 (a+b)(a-b)=a2-b2 Trigonometric expressions **Expression** | **Factorised form** sin2x+2sin x+1 | (sin x+1)2 4tan2x+4tan x+1 | (2tan x+1)2 9cos2x+12cos x+4 | (3cos x+2)2 sin2x-2sin x+1 | (sin x-1)2 cos2x-4cos x+4 | (cos x-2)2 tan2 2x-6tan 2x+9 | (tan 2x-3)2 sin2x-1 | (sin x-1)(sin x+1) 1-tan2 2x | (1-tan 2x)(1+tan 2x) 16-cos2x | (4-cos x)(4+cos x) Treat each ratio as one quantity. Check the middle term and the order of subtraction.