Question

Cine ma poate ajuta?​

Answer 1

Răspuns:

Explicație pas cu pas:

2) a₁ = 1 ; a₂ = 3  ; a₂ = a₁ + r =>

r = a₂-a₁ = 3-1 = 2

a₃ = a₂+r = 3+2 = 5 ; a₄ = a₃+r = 5+2 = 7 ;

a₅ = a₄+r = 7+2 = 9

S₅ = a₁+a₂+a₃+a₄+a₅ = 1+3+5+7+9 = >

S₅ = 25

3) f(x) = mx²-8x-3 ; f: R --> R

f max = 5 <=> mx²-8x-3 = 5 =>

mx² -8x+2 = 0 => x₁,₂ = [8 ±√(64-8m)]/2m

x = -b/2a ;  a = m ; b = -8 ; c = 2

x = 8/2m = 4/m = >

[8 ±√(64-8m)]/2m = 8/2m =>

8 ±√(64-8m) = 8 =>

±√(64-8m) = 0 =>

64 - 8m = 0 => 8m = 64 => m = 8