Answer:
a) 
b) 
Step-by-step explanation:
By definition, we have that the change rate of salt in the tank is
, where
is the rate of salt entering and
is the rate of salt going outside.
Then we have,
, and

So we obtain.
, then
, and using the integrating factor
, therefore
, we get
, after integrating both sides
, therefore
, to find
we know that the tank initially contains a salt concentration of 10 g/L, that means the initial conditions
, so 

Finally we can write an expression for the amount of salt in the tank at any time t, it is 
b) The tank will overflow due Rin>Rout, at a rate of
, due we have 500 L to overflow
, so we can evualuate the expression of a)
, is the salt concentration when the tank overflows
Answer:
F = 63
Step-by-step explanation:
28/44 = F/99
28/44 x 99 = F
F = 63
Answer:
<h2>X greater-than 0</h2>
Step-by-step explanation:
The given function is

Which is a logarithm function. An important characteristic of logarithms is that their domain cannot be negatice, because the logarithm of a negative number is undefined, the same happens for x=0.
Therefore, the domain of this function is all real numbers more than zero.
The image attached shows the graph of this function, there you can notice its domain restriction.
So, the right answer is the first choice: x greater than 0.
Answer:
π
2
,
3
⋅
π
2
,
3
⋅
π
4
,
7
⋅
π
4
Explanation:
Factorizing your equation we get
cot
(
x
)
=
0
so
cos
(
x
)
=
0
we get the following Solutions in the given interval
x
=
π
72
or
x
=
3
π
2
for the second case we get
cot
(
x
)
=
−
1
so
cos
(
x
)
=
−
sin
(
x
)
and we get
x
=
3
π
4
or
x
=
7
π
4
Hint:
To get the Solutions of the last equation you can use
√
sin
(
x
+
π
4
)
=
0
Step-by-step explanation: