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Ответ:
Объяснение:
[ sin^2a*(1-cos^2a) ] / cos^2a*sin^2a = sin^2a*sin^2a/sin^2a*cos^2a=
=sin^2a/cos^2a=tg^2a
1. x²-6x+9 = (x-3)².
2. 16-9y² = (4-3y)(4+3y).
3. 4x²+4x+1 = (2x+1)².
4. 36m⁴-25n² = (6m²-5n)(6m²+5n).
<span>5. a⁴-16 = (a</span>²-4)(a²+4) = (a-2)(a+2)(a²+4).