V=LWH
SA=2(LW+LH+WH)
V=240
first check that they are 240 volume
multiply numbers they should equal 240
the first one (A) can be eliminated since the dimentions are the same and therefor the surface areas are the same
2nd one check so far
3rd one (C) 6*4*15=360 which is wrong so eliminate this one
4th (d) 12*6*5=360 which is not 240 so eliminate
answer is B
Answer:
y = x*sqrt(Cx - 1)
Step-by-step explanation:
Given:
dy / dx = (x^2 + 5y^2) / 2xy
Find:
Solve the given ODE by using appropriate substitution.
Solution:
- Rewrite the given ODE:
dy/dx = 0.5(x/y) + 2.5(y/x)
- use substitution y = x*v(x)
dy/dx = v + x*dv/dx
- Combine the two equations:
v + x*dv/dx = 0.5*(1/v) + 2.5*v
x*dv/dx = 0.5*(1/v) + 1.5*v
x*dv/dx = (v^2 + 1) / 2v
-Separate variables:
(2v.dv / (v^2 + 1) = dx / x
- Integrate both sides:
Ln (v^2 + 1) = Ln(x) + C
v^2 + 1 = Cx
v = sqrt(Cx - 1)
- Back substitution:
(y/x) = sqrt(Cx - 1)
y = x*sqrt(Cx - 1)
Answer:
x is 10.3
Step-by-step explanation:
Your answer would be 15.6
