All AP Calculus AB Resources
Example Questions
Example Question #16 : Solving Separable Differential Equations And Using Them In Modeling
Solve the separable differential equation
given the initial condition
To solve the separable differential equation, we must separate x and y to the same sides as their respective derivatives:
Next, we integrate both sides:
The integrals were solved using the following rules:
,
The two constants of integration were combined to make a single constant.
Now, exponentiate both sides to isolate y, and use the properties of exponents to rearrange the integration constant:
(The exponential of the constant is another constant.)
Finally, we solve for the integration constant using the initial condition:
Our final answer is
Example Question #16 : Solving Separable Differential Equations And Using Them In Modeling
Solve the separable differential equation:
To solve the separable differential equation, we must separate x and y to the same sides as their respective derivatives:
Next, we integrate both sides:
The integrals were solved using the following rules:
,
The two constants of integration were combined to make a single one.
Now, we solve for y:
Because the problem statement said that y is negative - and y cannot be zero - our final answer is
Example Question #17 : Solving Separable Differential Equations And Using Them In Modeling
Solve the separable differential equation:
and at
To solve the separable differential equation, we must separate x and y to the same sides as their respective derivatives:
Next, we integrate both sides:
The integrals were solved using the following rules:
,
The two constants of integration were combined to make a single one.
Now, we exponentiate both sides to solve for y:
Using the properties of exponents, we can rearrange the integration constant:
(The exponential of the constant is itself a constant.)
Using the given condition, we can solve for C:
Our final answer is
Example Question #17 : Solving Separable Differential Equations And Using Them In Modeling
The rate of a chemical reaction is given by the following differential equation:
,
where is the concentration of compound at a given time, . Which one of the following equations describes as a function of time? Let be the concentration of compound when .
To begin with, the differential equation needs to be rearranged so that each variable is one side of the equation:
.
Then, integrate each side of the rate law, bearing in mind that will range from to , and time will range from to :
After integrating each side, the equation becomes:
.
The left side has to be evaluated from to , and the right side is evaluated from to :
. This becomes:
.
Finally, rearranging gives:
Example Question #19 : Solving Separable Differential Equations And Using Them In Modeling
Given that and , solve for . What is the value of ?
1
1
This is a separable differential equation. The simplest way to approach this is to turn into , and then by abusing the notation, "multiplying by dx" on both sides.
We then group all the y terms with dy, and all the x terms with dx.
Integrating both sides, we find
Here, the first integral is found by using substitution of variables, setting . In addition, we have chosen to only put a +C on the second integral, as if we put it on both, we would just combine them in any case.
To solve for y, we multiply both sides by two and raise e to both sides to get rid of the natural logarithm.
(Note, C was multiplied by two, but it's still just an arbitrary constant. If you prefer, you may call the new C value .)
Now we drop our absolute value signs, and note that we can take out a factor of and stick in front of the right hand side.
As is just another arbitrary constant, we can relabel this as C, or if you prefer. Solving for y gets us
Next, we plug in our initial condition to solve for C.
;
Leaving us with a final equation of
Plugging in x = 4, we have a final answer,
Example Question #21 : Applications Of Antidifferentiation
Solve the separable differential equation:
given the condition at
To solve the separable differential equation, we must separate x and y to the same sides as their respective derivatives:
Next, we integrate both sides:
;
The integrals were solved using the identical rules.
The two constants of integration are now combined to make a single one:
Now, exponentiate both sides of the equation to solve for y, and use the properties of exponents to rearrange C:
Finally, we solve for the integration constant using the given condition:
Our final answer is
Example Question #1 : Interpretations And Properties Of Definite Integrals
If f(1) = 12, f' is continuous, and the integral from 1 to 4 of f'(x)dx = 16, what is the value of f(4)?
27
12
28
4
16
28
You are provided f(1) and are told to find the value of f(4). By the FTC, the following follows:
(integral from 1 to 4 of f'(x)dx) + f(1) = f(4)
16 + 12 = 28
Example Question #1 : Interpretations And Properties Of Definite Integrals
Find the limit.
lim as n approaches infiniti of ((4n3) – 6n)/((n3) – 2n2 + 6)
1
–6
4
nonexistent
0
4
lim as n approaches infiniti of ((4n3) – 6n)/((n3) – 2n2 + 6)
Use L'Hopitals rule to find the limit.
lim as n approaches infiniti of ((4n3) – 6n)/((n3) – 2n2 + 6)
lim as n approaches infiniti of ((12n2) – 6)/((3n2) – 4n + 6)
lim as n approaches infiniti of 24n/(6n – 4)
lim as n approaches infiniti of 24/6
The limit approaches 4.
Example Question #41 : Integrals
If a particle's movement is represented by , then when is the velocity equal to zero?
The answer is seconds.
now set because that is what the question is asking for.
seconds
Example Question #4 : Interpretations And Properties Of Definite Integrals
A particle's movement is represented by
At what time is the velocity at it's greatest?
The answer is at 6 seconds.
We can see that this equation will look like a upside down parabola so we know there will be only one maximum.
Now we set to find the local maximum.
seconds
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