Questions tagged [gre-exam]
For questions relevant to the general or subject-specific Graduate Record Examination, abbreviated GRE.
401
questions
0
votes
0
answers
48
views
What is the largest order of an element in the group of permutations of $n$ objects?
I have a very little knowledge in abstract algebra and want to know what does the problem actually mean.
I encountered this question in the official test
$\text{Graduate Record Examination - Math ...
- 4,547
0
votes
2
answers
79
views
GRE - Standard Deviation Question (Quantitative Comparasion)
Each video game that a video game shop sold last year was either for the PS4 or Xbox One. The shop sold new PS4 Games for USD 60 and new Xbox One Games for USD 30. The standard deviation for all of ...
0
votes
1
answer
58
views
Distance and Arc Length (Math GRE)
A circular helix in $xyz$-space has the following parametric equations, where $\theta \in \mathbb{R}$.
$x(\theta)= 5\cos(\theta)$
$y(\theta)=5\sin(\theta)$
$z(\theta)=\theta$
Let $L(\theta)$ be the ...
- 131
0
votes
1
answer
50
views
Finite sum inequality (math GRE subject)
Which of the following statements are true:
There exists a constants $C$ such that $\log x \leq C\sqrt x$ for all $x\geq1$
There exists a constant $C$ such that $\sum_{k=1}^nk^2 \leq Cn^2$ for all ...
- 131
1
vote
3
answers
86
views
Evaluating ${\int_{0}^{1}\sqrt{1+\frac{1}{3x}}\text{ d}x}$ using $\int f^{-1}(x)dx=x f^{-1}(x)-F(f^{-1}(x))+C$
While studying, I countered problem $\text{#}2$ here. $\text{(UCHICAGO REU 2019 - MATH GRE PREP: WEEK 2)}$.
I saw this also. But wanted to know if my way is also correct (regardless of the time ...
- 4,547
4
votes
0
answers
102
views
Is this a valid way to compute $\int_{0}^{\infty}\frac{\cos(\alpha x)-\cos(\beta x)}{x}\text{d}x$?
I am not sure if the following way is valid to evaluate
$$\int_{0}^{\infty}\frac{\cos(\alpha x)-\cos(\beta x)}{x}\text{d}x$$
SOURCE
I saw this and this
But I am asking if the following is valid or not?...
- 4,547
0
votes
0
answers
29
views
Approximate Binomial Distribution using normal distribution
When I was reading "cracking the GRE mathematics subject test" 4th edition page 282, there is a formula regarding approximation of binomial distribution:
In X ~ Binomial(n, p), when n is ...
- 29
0
votes
0
answers
112
views
How $5^{40} < 4^{60} < 27^{30}$, $8^{1/11} < 9^{1/10} < 10^{1/9}$, $e^{e} < \pi^{e} < e^{\pi}$, and $200^{100} < 200! < 100^{200}$?
The following four problems appeared in (UCLA) (University of California, Los Angeles) - GRE Preparation.
$\mathbf{Problem} \space \mathbf{11}, \mathbf{Problem} \space \mathbf{12}, \mathbf{Problem} \...
- 4,547
0
votes
0
answers
76
views
If $f(x)=p \sin x + q x \cos x + x^2$ and $f(2)=3$, find $f(-2)$
A GRE subject trig question:
Let $p,q$ be constants and let $$f(x)=p \sin x + q x \cos x + x^2$$ for all real numbers $x$. If $f(2)=3$, find $f(-2)$.
So I plug in and obtain
$$3=\phantom{-}p \sin 2 +...
- 2,981
0
votes
0
answers
32
views
Finding relative extrema
For the following problem, we are asked which of the following statements is true for $f(x,y)=x^2-2xy+y^3$
A) $f$ has all its relative extrema on the line $y=x$
B) $f$ has all its relative extrema on ...
- 131
1
vote
1
answer
122
views
If a $3\times 3$ matrix satisfies $A^3-A^2-A+I=0$, then it is not necessarily diagonalisable.
If a $3\times 3$ matrix satisfies $A^3-A^2-A+I=0$, then it is not necessarily diagonalisable.
I have a counterexample
$\begin{pmatrix}1&1&0\\0&1&0\\0&0&1\end{pmatrix}$. But I ...
3
votes
1
answer
136
views
Showing that $AB$ is a subgroup.
I was trying to solve this question:
Let $G$ be a group and $A,B$ subgroups of $G.$ Define $AB$ as the set of all products $ab,$ where $a \in A$ and $b \in B.$ Prove that $AB$ is a subgroup of $G$ iff ...
- 1,299
0
votes
1
answer
55
views
Matrix in $M_2(\mathbf{R})$ of order $2$ has trace $0$
I found this question in a GRE math subject test from 1987. It's problem 61 at http://web.math.ucsb.edu/~padraic/ucsb_2014_15/math_gre_w2015/GRE_8767_test.pdf. It boils down to the following.
Prove ...
- 4,249
0
votes
0
answers
35
views
$u=f(x,y)$ and the partial derivatives are themselves differentiable functions of $x$ and $y$ (Typo?)
I am really not sure whether this question can be posted in MSE or not, but hopefully can be. If not, kindly do not downvote, but suggest me to delete it from here and post it somewhere else.
While ...
- 4,547
2
votes
1
answer
503
views
Let $h$ be the function defined by $h(x)=\int_{0}^{x^2}e^{x+t}dt$ for all real numbers $x$. Then $h'(1)=\dots$
This question appeared in the GRE MATH SUBJECT TEST (GR$0568$) - Question# $24$:
Let $h$ be the function defined by $h(x)=\int_{0}^{x^2}e^{x+t}dt$ for all real numbers $x$. Then $h'(1)=$
(A) $e-1$
(...
- 4,547
1
vote
1
answer
139
views
Possible dimensions of $V \cap W$ in $\mathbb{R}^n$
If $V$ and $W$ are two dimensional subspaces of $\mathbb{R}^n$, what are the possible dimensions of $V \cap W$ if;
$V$ and $W$ have the same dimensions? (for example; $\dim(V)=2, \dim(W)=2, n=3$)
$V$ ...
- 4,547
1
vote
1
answer
41
views
The order of $C=\sum_{k=0}^{90}(90-k)\cos(k ^{\circ}), S=\sum_{k=0}^{90}(90-k)\sin(k ^{\circ})$, and $T=\sum_{k=0}^{90}(90-k)\tan(k ^{\circ})$.
This is multiple choice questions, where using calculators is not allowed. Candidates have, on average, $2$ minutes $30$ seconds to solve it.
MY ATTEMPT:
$k ^{\circ} = (\text{positive constant} \...
- 4,547
1
vote
2
answers
263
views
Let $P$ be a polynomial with integer coefficients satisfying $P(0)=1, P(1)=3, P'(0)=-1, P'(1)=10$. What is the minimum possible degree of $P$?
I am preparing for GRE MATH SUBJECT TEST, I have reviewed many problems, some of these problems are not in GRE Math Practice books, but they are in some other books. I found the following problem, but ...
- 4,547
0
votes
2
answers
139
views
Is $\text{for}\ n\in \mathbb{N},\dfrac{u_{n+1}}{u_n}=q \iff \text{for}\ n\in \mathbb{N},u_{n+1}=q u_n$?
In the correction of bac exams in my country , The Correction Committee ordered us to give the whole point for students who they showed that the sequence $u_n$ is geometric using $u_{n+1}=q u_n$ ...
- 6,816
2
votes
2
answers
306
views
Preimage of Closed Set Under a Continuous Map Isn't Closed?
Problem: In the $xy$-plane, the graph of $x^{\log y} = y^{\log x}$ is
(A) Empty
(B) A single point
(C) A ray in the open first quadrant
(D) A closed curve
(E) The open first quadrant
Here is ...
- 7,382
2
votes
2
answers
1k
views
Integral of the Product of a Function and Its Derivative
Problem: Let $f$ be a function such that the graph of $f$ is a semicircle $S$ with end points $(a,0)$ and $(b,0)$, where $a < b$. The improper integral $\int_{a}^{b} f(x) f'(x) dx$ is
(A) ...
- 7,382
1
vote
2
answers
87
views
For what values of t does the eigenvalues $\lambda_1$,$\lambda_2$ has the value $\lambda_1$+$\lambda_2$ = 1.
Do not know how to solve it, could anyone help me please?
- 2,007
0
votes
2
answers
109
views
Determining the number of gallons of fuel that the car used on the trip.
My answer was (C), where I was thinking while I was solving how the unit could be Gallons only, but the correct answer is (A), I do not know why my answer is wrong and why (A) is the correct answer, ...
- 2,007
2
votes
1
answer
3k
views
Is this Enough for the Math Subject GRE? [closed]
I have been studying for the math GRE for quite sometime now. I have been going through the princeton review and old GRE tests, and in fact without much very difficulty at all. As a way of getting ...
- 7,382
0
votes
2
answers
178
views
Determining the value of the product of a matrix A with another known matrix without knowing what is the matrix A (math GRE subject test 9768 Q.43)
I have given the entries of the matrix the names $a$,$b$,$c$,$\dots$,$i$, and I multiplied the matrix by the given $2$ matrices. But the problem is that I have for every $3$ entries $2$ equation in $3$...
- 2,007
0
votes
0
answers
144
views
Does the math subject GRE exam contains a graph paper and a calculator or no.
I know that the math subject GRE exam is a paper based test, but does this paper contains a graph paper? I also have read(not sure from the source) that calculators are not allowed on this test, even ...
- 2,007
0
votes
1
answer
80
views
Knowing 3 points of a figure, the fourth point can take how many values so that the given figure form a parallelogram. (GRE exam 9768 Q.42)
I do not know how to solve it, could anyone give me a hint? or tell me if this question How to test whether a set of four points can form a parallelogram is useful in the solution or irrelevant?
- 2,007
0
votes
2
answers
70
views
Determining the relative maximum of a 2 variable function in less than 2.5 minuites.(GRE Exam 9768 Q.41)
I know that I have to calculate the gradient of $f$, equate it to zero to find the critical points, calculate A,B,C,$\vartriangle$, then if $\vartriangle$ < 0 & A < 0 then f has relative(...
- 2,007
3
votes
2
answers
2k
views
Closure in the Discrete Topology
If $\tau$ is the discrete topology on the real numbers, find the closure of $(a,b)$
Here is the solution from the back of my book:
Since the discrete topology contains all subsets of $\Bbb{R}$, ...
- 7,382
1
vote
1
answer
401
views
Cauchy Number of a Permutation
Find the Cauchy number for the permutation $(1354)(267)$.
I did a google search on the definition of a Cauchy number, but nothing really came up. This is the best I could find, but it is rather ...
- 7,382
0
votes
3
answers
270
views
Calculating the probability that more of a fair coin tosses will result in heads than in tails.
My thought was the probability is: $\frac{5}{8} + \frac{6}{8} + \frac{7}{8} + 1$ and the sum is $\frac{13}{4}$ but this is not one of the choices. and the correct answer is E. I do not know why my ...
- 2,007
3
votes
1
answer
187
views
Domain of the Function Defined in Terms of a Series
The domain of the function $f(x) = \int (x+2x^2 + 3x^3 + ...)dx$ is...
I just want to find out whether the method I used to arrive at the solution is valid. In finding the domain, I first noted that $...
- 7,382
-1
votes
2
answers
218
views
The greatest value of Riemann sum and integral of a function on the interval [0,10]
My answer was D, but the correct answer is B, I do not no why my answer is wrong and why B is the correct answer and why other answers are wrong. Could anyone explain this for me?
- 2,007
0
votes
2
answers
1k
views
Matrix Representation of a Bilinear Form
Let $b : \Bbb{R}^2 \times \Bbb{R}^2 \to \Bbb{R}$ be the bilinear form defined by $$b((x_1,x_2),(y_1,y_2)) = x_1 y_1 - 2x_1 y_2 + x_2 y_1 + 3x_2 y_2.$$ Find the $2 \times 2$ matrix $B$ of $b$ relative ...
- 7,382
0
votes
4
answers
112
views
How can I solve this question without using calculator and in only 2.5 minuites.
This is a math subject GRE exam question, that I know how to solve but in more than 2.5 minuets and using a calculator, may be there is some intuition for solving this question that I do not know that ...
- 2,007
2
votes
2
answers
128
views
Solution to Integral Equation
Which of the following is a solution of $u(x) = x + \int_{0}^{x} (t-x)u(t)dt$??
(A) $\sin x$
(B) $x \cos x$
(C) $\ln (x+1)$
(D) $x e^{-x}$
(E) $xe^x$
Since all of the choices are twice differentiable,...
- 7,382
-1
votes
3
answers
360
views
For how many values of $x$ are the median and the mean are equal? [closed]
I know how to calculate the mean and the median, but I do not know how to solve this. Could anyone help me please?
- 2,007
-1
votes
1
answer
356
views
Calculating the equation of the plane tangent to a given surface in xyz space. [closed]
The solution is written below and I understood all the solution until saying that the value of z is 1, but I do not understand the rest, why z + x = 1, could anyone clarify this for me please ?
- 2,007
-2
votes
3
answers
354
views
Limits at infinity of a function and its derivative [closed]
I do not know how to solve this question, could anyone help me please?
- 2,007
2
votes
3
answers
5k
views
Number of integers between 1 and 1000 that are divisible by 30 but not divisible by 16.
I know that the number of integers between 1 and 1000 that are divisible by 30
is 33, and the number of integers between 1 and 1000 that are divisible by 16 is 62, but I do not know how to calculate ...
- 2,007
2
votes
2
answers
224
views
Using the rational root test (subject Math GRE exam 9768 Q.31)
I used the rational root test and my answer was B as -5 does not divide 9, but the correct answer is C. Could anyone clarify this for me please?
- 2,007
1
vote
3
answers
130
views
Math subject GRE exam 9768 Q.30 (condition that a basis of a real vector space must satisfy)
I am sure that A,B and E are wrong, but I do not know which is right C or D, and why, could anyone help me please?
- 2,007
0
votes
1
answer
410
views
Sets Whose Elements Sum to an Even Integer
From the set of integers $\{1,...,9\}$, how many nonempty subsets sum to an even integer.
This is probably trivial for most, but I am notoriously bad at counting, so I just want to make sure I am ...
- 7,382
1
vote
1
answer
120
views
Calculating the value of a definite integral knowing the value of the integrand and its derivative on the boundaries.
I do not know how the givens are useful in solving this question:
Could anyone help me please?
- 2,007
0
votes
3
answers
2k
views
What is the smallest possible dimension $V_1$ intersection $V_2$ must have.
My answer was $A$ because the two vector spaces may be disjoint and hence intersection is $\{0\}$ whose dimension is zero by convention, but the correct answer is $C$.
Could anyone clarify this for ...
- 2,007
0
votes
1
answer
1k
views
Let $f$ be a function such that $f(x) = f(1-x)$ for all real numbers $x$. If $f$ is differentiable everywhere, then $f'(0)$
I do not know how to solve this question:
Could anyone help me please?
- 2,007
0
votes
3
answers
289
views
Math subject GRE test 9768 Q.26
What is the fastest way to solve this question?
I checked and I found that the derivative exists at $x = 1$.
- 2,007
2
votes
2
answers
158
views
Weird GRE mistake [duplicate]
According to the answer key, the correct answer is (a).... This is obviously a mistake, right? If a square matrix is invertible, then it has full rank.
- 1,172
1
vote
2
answers
264
views
Determining the maximum value of a multivariable function under 4 inequality constraints.(Math GRE subject test 9768 Q.25)
I know that I should use Lagrange multiplier method, but how with the inequality constraints? could anyone help me please?
- 2,007
0
votes
2
answers
401
views
A basis for a subspace of Euclidean 4-space consisting of all vectors orthogonal to 2 vectors.(Math subject GRE 9768 Q.24)
The question is in the following picture:
The answer is C.
I know the method of finding all vectors orthogonal to a vector,but it will take a long time if I applied for 2 vectors, as I must answer ...
- 2,007