All GRE Subject Test: Math Resources
Example Questions
Example Question #1 : Taylor And Maclaurin Series
Let
Find the the first three terms of the Taylor Series for centered at .
Using the formula of a binomial series centered at 0:
,
where we replace with and , we get:
for the first 3 terms.
Then, we find the terms where,
Example Question #1 : Taylor's Theorem
Determine the convergence of the Taylor Series for at where .
Conditionally Convergent.
Inconclusive.
Divergent.
Does not exist.
Absolutely Convergent.
Absolutely Convergent.
By the ratio test, the series converges absolutely:
Example Question #1 : Taylor And Maclaurin Series
Find the interval of convergence for of the Taylor Series .
Using the root test
and
. T
herefore, the series only converges when it is equal to zero.
This occurs when x=5.
Example Question #1 : Taylor And Maclaurin Series
Suppose that the derivative of a function, denoted , can be approximated by the third degree Taylor polynomial, centered at :
If , find the third degree Taylor polynomial for centered at .
To get , we need to find the antiderivative of by integrating the third degree polynomial term by term.
We only want up to a third degree polynomial, so we can disregard the fourth order term:
Since , substitute for the final .
Example Question #1 : Taylor Series
Write out the first four terms of the Taylor series about for the following function:
The Taylor series about x=a of any function is given by the following:
So, we must find the zeroth, first, second, and third derivatives of the function (for n=0, 1, 2, and 3 which makes the first four terms):
The derivatives were found using the following rule:
Now, evaluated at x=a=1, and plugging in the correct n where appropriate, we get the following:
which when simplified is equal to
.
Example Question #5 : Taylor And Maclaurin Series
Find the first two terms of the Taylor series about for the following function:
The general formula for the Taylor series about x=a for a function is
First, we must find the zeroth and first derivative of the function.
The zeroth derivative of a function is just the function itself, so we only have to find the first derivative:
The derivative was found using the following rule:
Now, write the first two terms of the sequence (n=0 and n=1):
Example Question #6 : Taylor And Maclaurin Series
Write out the first three terms of the Taylor series for the following function about :
The general formula for the Taylor series of a given function about x=a is
.
We were asked to find the first three terms, which correspond to n=0, 1, and 2. So first, we need to find the zeroth, first, and second derivative of the given function. The zeroth derivative is just the function itself.
The derivatives were found using the following rules:
,
Now use the above formula to write out the first three terms:
Simplified, this becomes
Example Question #1 : Integrals
Integrate:
This problem requires U-Substitution. Let and find .
Notice that the numerator in has common factor of 2, 3, or 6. The numerator can be factored so that the term can be a substitute. Factor the numerator using 3 as the common factor.
Substitute and terms, integrate, and resubstitute the term.
Example Question #1 : Integrals
Evaluate the following integral:
To calculate this integral, we could expand that whole binomial, but it would be very time consuming and a bit of a pain. Instead, let's use u substitution:
Given this:
We can say that
Then, plug it back into our original expression
Evaluate this integral to get
Then, replace u with what we substituted it for to get our final answer. Note because this is an indefinite integral, we need a plus c in it.
Example Question #3 : Integrals
Integrate the following using substitution.
Using substitution, we set which means its derivative is .
Substituting for , and for we have:
Now we just integrate:
Finally, we remove our substitution to arrive at an expression with our original variable:
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