(50/1+e^ -x)=4?

Question

Please show steps

Answer 1

50/(1 + (e^-x)) = 4
1 + e^(-x) = (50/4)
1 + e^(-x) = (25/2)
e^(-x) = (25/2) - 1
e^(-x) = (25/2) - (2/2)
e^(-x) = (25 - 2)/2
e^(-x) = (23/2)
1/(e^x) = (23/2)
e^x = 1/(23/2)
e^x = (1/1)/(23/2)
e^x = (1/1)*(2/23)
e^x = (2/23)
x = ln(2/23)
x = -2.44235

Answer 2

There is no Answer to this Question!


echo -no
number_of_space_dimensions 2
materi_velocity
materi_stress
materi_strain_total
materi_strain_plasti
materi_plasti_kappa
end_initia

(start mesh)
node 1 0 0
node 2 1 0
node 3 0 1
node 4 1 0.9
node 5 -1 0
node 6 -1 1
node 7 2 0
node 8 2 0.9
element 1 -quad4 1 2 3 4
element 2 -quad4 5 1 6 3
element 3 -quad4 2 7 4 8

(start guess for velocity field)
node_dof -ra -from 1 -to 8 -ra 1. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.

(right edge)
geometry_line 1 2. 0. 2. 1. 1.e-4
(lower edge)
geometry_line 2 -1. 0. 2. 0. 1.e-4
(left edge)
geometry_line 3 -1. 0. -1. 1. 1.e-4
(upper right edge)
geometry_line 4 1. 0.9 2. 0.9 1.e-4
(oblique edge)
geometry_line 5 0. 1. 1. 0.9 1.e-4

(left edge, lower edge, right edge )
geometry_set 1 -geometry_line 1 -geometry_line 2 -geometry_line 3

(boundary conditions)
bounda_unknown 0 -geometry_set 1 -vely
bounda_time 0 0. 0. 100. 0.
bounda_unknown 1 -geometry_line 1 -velx
bounda_time 1 0. 1. 100. 1.
bounda_unknown 2 -geometry_line 3 -eptxx -eptxy -eptxz -eptyy -eptyz -eptzz
-eppxx -eppxy -eppxz -eppyy -eppyz -eppzz
-kap
bounda_time 2 0. 0. 100. 0.

(eulerian calculation)
options_mesh -fixed_in_space -fixed_in_space
slide_geometry 1 -geometry_line 5

(updated lagrangre material; hardening von mises)
group_type 0 -materi
group_materi_elasti_young 0 7000.
group_materi_elasti_poisson 0 0.2
group_materi_memory 0 -updated
group_integration_points 0 -minimal

dependency_item 1 -group_materi_plasti_vonmises 0 -kap 2
dependency_diagram 1 0. 1. 24.3 248.3

(post_point in outflow edge)
post_point 1 2. 0.5
post_calcul -materi_stress -sizedev -materi_strain_plasti -sizetot

(more elements)
control_mesh_refine_globally 2 -h_refinement
control_mesh_refine_globally 3 -h_refinement
control_mesh_refine_globally 4 -h_refinement
control_mesh_refine_globally 5 -h_refinement

(time steps)
control_timestep 20 2.e-2 5.
(
control_print 20 -time_current -control_repeat -post_point_dof_calcul
control_print_history 20 -post_point_dof_calcul 1 0
)

(some arbitrary value is checked)
target_item 0 -post_point_dof_calcul 1 0
target_value 0 15.131 1.

Answer 3

(50/1+e^ -x)=4

multiply both sides by 1+e^-x

50 = 4(1+e^-x)
50 = 4 + 4e^-x ... Distribute the 4
46 = 4e^-x ... Subtract the 4
11.5 = e^-x ... Divide 46/4
take the natural log (ln) of both sides (you need a graphic calculator)

since x is negative, you take the recipricol of 11.5 , which is 2/23

ln(2/23) = -2.4423

Answer 4

50/(1+e^-x) = 4
Multiply both sides by 1 + e^-x
50 = 4(1+e^-x)
Distribute the 4
50 = 4 + 4e^-x
Subtract 4 from both sides
46 = 4e^-x
Divide both sides by 4
46/4 = e^-x
Reduce 46/4
23/2 = e^-x
Take the natural log of both sides
ln(23/2) = ln(e^-x)
ln and e are inverse functions; therefore,
ln(23/2) = -x
Multiply both sides by -1
-ln(23/2) = x
Exact answer: x = -ln(23/2)
Approximate answer: x = -2.44234703537

Answer 5

50/(1+e^-x)=4
50=4+4e^-x
e^-x=11.5
TAKING In both sides
x= -In11.5

= -2.442347036

Answer 6

(1/50)(50/1+e^-x)=4(1/50)
1/1+e^-x=4/50
4+4e^.x=50
4e^-x=46
e^-x=46/4
ln (e^-x)=ln(46/4)
-x=ln(46/4)
x=-(ln(46/4))
no calculator, so find the exact answer that way

Answer 7

(50/1+e^ -x)=4
e^-x=4-50/1=-46
ln(e^-x)=-x=ln(-46)
ln(-46) is undefined therefore there is no answer.

Answer 8

(1+e^-x)/50 = .25
1+e^-x = 12.5
e^-x = 11.5
-x = ln11.5
x = -ln11.5

Answer 9

suppose x?