Answer:
0.26 and 0.577
Step-by-step explanation:
Given :
x :___0 ___ 1 ____ 2 ____ 3
f(x):_0.80 _0.15__0.04 __0.01
The mean :
E(X) = Σ(x * p(x))
E(X) = (0*0.8) + (1*0.15) + (2*0.04) + (3*0.01)
E(X) = 0 + 0.15 + 0.08 + 0.03
E(X) = 0.26
Var(X) = Σx²*p(x)) - E(x)²
Σx²*p(x)) = (0^2*0.8) + (1^2*0.15) + (2^2*0.04) + (3^2*0.01) = 0.4
Σx²*p(x)) - E(x)² = 0.4 - 0.26² = 0.3324
Std(X) = √0.334 = 0.577
Cds 3 dvds 5
Sue will use 6 shelves with 3 cds on each and 5 dvds on each.
1: right triangle, 2: right triangle, 3: not a right triangle, 4:not a right triangle.
Answer:
the height of the porch is H=1.91 m
Step-by-step explanation:
neglecting friction and assuming that the porch is horizontal, then the horizontal speed is v₀= 4 m/s and it does not change , thus he hits the base at
t= L/v₀ , L= horizontal distance
then for vertical motion , since the vertical velocity vy is 0 , the initial height is H ( the height of the porche) and the final height hf is 0 , we have
hf = H + vy*t - 1/2*g*t²
0 = H + 0 -1/2*g*t²
H = 1/2*g*t² = 1/2*g*(L/v₀)²
replacing values with g= gravity = 9.8 m/s²
H = 1/2*g*(L/v₀)² = 1/2*9.8 m/s² *( 2.5 m/ 4 m/s)² = 1.91 m
therefore the height of the porch is H=1.91 m
