Question

AJUTOR VA ROG MULȚUMESC!​

Answer 1

Conditie de existenta pt Cᵃₙ unde n >/ a

deci x+3 >/ 2 => x >/ -1 , x apartine [-1, infinit)

C²ₓ₊₃ = (x+3)!/[2! * (x+3-2)!] = (x+3)!/(x+1)! *2 = [(x+1)!(x+2)(x+3)]/(x+1)! * 2=

(x+2)(x+3)/2 = (x²+5x+6)/2

(x²+5x+6)/2 </ 6

x²+5x + 6 </ 12

x² +5x -6 </ 0

x² +6x-x -6 </ 0

x(x+6)-(x+6) </ 0

(x+6)(x-1) </ 0

x + 6 </ 0 => x </ -6

x-1 </ 0 => x </ 1

x apartine [-6, 1 ]