1+ctg2x=-1/sin2x
sin2x/sin2x + cos2x/sin2x + 1/ sin2x =0
sin2x+cos2x+1=0
cos^2 x - sin^2 x +2 sinxcosx+ cos^2x + sin^2x=0
2sinxcosx+2cos^2x=0
2cosx(sinx+1)=0
cosx=0
x=П/2 +Пn
sinx=-1
x= -- П/2 +Пn
А)(2-с)(2+с)-с(6-с)=4-с^2-6с+с^2=4-6с
Б)11,2
Вроде так
(2/(n+1)! - 3/n!) : (5/n!- 4n/(n+1)!)
1) 2/ (n+1)! -3/ n!= 2/(n+1)! - 3(n+1)/(n+1)! = (2-3n-3) / (n+1)!
2) 5/n! - 4n/(n+1)! = (5(n+1) -4n) / (n+1)! = (n+5)/ (n+1)!
3) (-3n-1)/ (n+1)! : ((n+5)/(n+1)!)= (-3n-1)(n+1)! / (n+1)!(5+n) =
= (-3n-1) / (5+n)
ответ при n = 2
2²⁰=(2⁴)⁵,
2⁴⁸ = (2⁴)¹²,
2⁸=(2⁴)²,
16⁹=(2⁴)⁹,
256=2⁸=(2⁴)².
5а×2b2-5a×3ab-a2b+6ab2
ab×(5×2b-5×3a-a+6b)
an×(10b-15a-a+6b)
an×(16b-16a)
an×16(b-a)
16ab×(b-a)