My friend needs help with this can someone help
1 answer:
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Answer:
x(t) = 581.66 lb
Step-by-step explanation:
From the given information:
Consider the salt quantity in the tank at time t be x(t) lb.
∴ the rate of change of salt content in the tank is
where:
the rate of inflow = salt conc. × flow rate = 3 lb/gallon × 7 gallons
=21 lb/s
rate of outflow = salt conc. in the tank × flow rate
= x/250 × 9
= 9x/250 lb/s
∴
This is a 1st order linear differentiation,
The integrating factor if
∴
at t = (0) and x(0) = 100 lb
Hence;
∴
after time t = 1 minute i.e 60 s
x(t) = 581.66 lb
Answer:
The polar coordinates are as follow:
a. (6,2π)
b. (18, π/3)
c. (2√2 , 3π/4)
d. (2, 5π /6)
Step-by-step explanation:
To convert the rectangular coordinates into polar coordinates, we need to calculate r, θ .
To calculate r, we use Pythagorean theorem:
r = ---- (1)
To calculate the θ, first we will find out the θ ' using the inverse of cosine as it is easy to calculate.
So, θ ' = cos ⁻¹ (x/r)
If y ≥ 0 then θ = ∅
If y < 0 then θ = 2 π − ∅
For a. (6,0)
Sol:
Using the formula in equation (1). we get the value of r as:
r =
r = 6
And ∅ = cos ⁻¹ (x/r)
∅ = cos ⁻¹ (6/6)
∅ =cos ⁻¹ (1) = 2π
As If y ≥ 0 then θ = ∅
So ∅ = 2π
The polar coordinates are (6,2π)
For a. (9,9/)
Sol:
r = 9 + 3(3) = 18
and ∅ = cos ⁻¹ (x/r)
∅ = cos ⁻¹ (9/18)
∅ = cos ⁻¹ (1/2) = π/3
As If y ≥ 0 then θ = ∅
then θ = π/3
The polar coordinates are (18, π/3)
For (-2,2)
Sol:
r =√( (-2)²+(2)² )
r = 2 √2
and ∅ = cos ⁻¹ (x/r)
∅ = cos ⁻¹ (-2/ 2 √2)
∅ = 3π/4
As If y ≥ 0 then θ = ∅
then θ = 3π/4
The polar coordinates are (2√2 , 3π/4)
For (-√3, 1)
Sol:
r = √ ((-√3)² + 1²)
r = 2
and ∅ = cos ⁻¹ (x/r)
∅ = cos ⁻¹ ( -√3/2)
∅ = 5π /6
As If y ≥ 0 then θ = ∅
So θ = 5π /6
The polar coordinates are (2, 5π /6)