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GRE Math: Common Errors

Subjects : gre, math

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. (a^-1)/a^5
413.03 / 10^4 (move the decimal point 4 places to the left)
75:11
A circle centered at -2 - -2 with radius 3.
1/a^6

2. What are the real numbers?
I
All the numbers on the number line (negative - rational - irrational - decimal - integer). All the numbers on the GRE are real. (-2 - 1 - .25 - 1/2 - pi)
The two xes after factoring.
N! / (k!)(n-k)!

3. x^(-y)=
1/(x^y)
2 & 3/7
4sqrt3. The triangle can be divided into two equal 30-60-90 triangles with side 6 as the side in which 6 = xsqrt3. So x =2sqrt3...
y = 2x^2 - 3

4. Number of degrees in a triangle
90
A circle centered on the origin with radius 8.
180
52

5. Ratio of ages of Anna and Emma is 3:5 and of Emma and Nicolas is 3:5. What is the ratio of Anna to Nicholas' ages?
9 : 25
The greatest value minus the smallest.
55%
2sqrt6

6. What is the graph of f(x) shifted downward c units or spaces?
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
12.5%
F(x) - c
13pi / 2

7. a^2 - b^2 =
1.0843 X 10^11
(a - b)(a + b)
180
III

8. What is a tangent?
The set of output values for a function.
4.25 - 6 - 22
(a + b)^2
A tangent is a line that only touches one point on the circumference of a circle.

9. Suppose that the graph of f(x) is the result of stretching y=x + 5 away from the x-axis by a factor of 2. What is the new equation for the graph f(x)?
12.5%
A subset.
II
y = (x + 5)/2

10. 1:sqrt3:2 is the ratio of the sides of what kind of triangle?
A set with a number of elements which can be counted.
(a - b)^2
N! / (n-k)!
A 30-60-90 triangle.

11. x^6 / x^3
From northeast - counterclockwise. I - II - III - IV
1:sqrt3:2
28. n = 8 - k = 2. n! / k!(n-k)!
x^(6-3) = x^3

12. P and r are factors of 100. What is greater - pr or 100?
Indeterminable.
A tangent is a line that only touches one point on the circumference of a circle.
72
...multiply by 100.

13. Order of quadrants:
72
48
13pi / 2
From northeast - counterclockwise. I - II - III - IV

14. What is a set with no members called?
1:1:sqrt2
III
70
The empty set - denoted by a circle with a diagonal through it.

15. 70 < all primes< 80
71 - 73 - 79
(amount of decrease/original price) x 100%
x^(4+7) = x^11
Even

16. What is the maximum value for the function g(x) = (-2x^2) -1?
13pi / 2
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
67 - 71 - 73
1

17. If the two sides of a triangle are unequal then the longer side...
Its last two digits are divisible by 4.
Lies opposite the greater angle
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
11 - 13 - 17 - 19

18. Which quandrant is the lower right hand?
4a^2(b)
An infinite set.
IV
3

19. What is the graph of f(x) shifted right c units or spaces?
90pi
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
F(x-c)
A subset.

20. 25^(1/2) or sqrt. 25 =
5 OR -5
The shortest arc between points A and B on a circle'S diameter.
A central angle is an angle formed by 2 radii.
(p + q)/5

21. Formula to find a circle'S circumference from its diameter?
288 (8 9 4)
An isosceles right triangle.
C = (pi)d
(a - b)(a + b)

22. Circumference of a circle?
16.6666%
Move the decimal point to the right x places
Diameter(Pi)
4.25 - 6 - 22

23. What is the set of elements which can be found in either A or B?
The union of A and B.
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
x^(6-3) = x^3
4725

24. If you have a set of n objects - but you only want to order k of them - what formula do you use to determine the number of permutations?
N! / (n-k)!
2.4. We calculate the area (6) and then turn the triangle on its side and use x as the height to calculate again. (5x)/2=6
x^(2(4)) =x^8 = (x^4)^2
(a - b)(a + b)

25. a^2 + 2ab + b^2
1 & 37/132
(a + b)^2
23 - 29
0

26. What does scientific notation mean?
A reflection about the axis.
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
23 - 29
The overlapping sections.

27. What is the 'Range' of a series of numbers?
y = 2x^2 - 3
The longest arc between points A and B on a circle'S diameter.
y = (x + 5)/2
The greatest value minus the smallest.

28. Suppose that the graph of f(x) is the result of sliding the graph of y=2x^2 down 3 units of spaces. What is the new equation?
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
IV
y = 2x^2 - 3
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15

29. Find the surface area of a cylinder with radius 3 and height 12.
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
90pi
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
A tangent is a line that only touches one point on the circumference of a circle.

30. Is 0 even or odd?
Even
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
A = pi(r^2)
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.

31. A brick with dimensions 10. 15 and 25 weighs 1.5 kg. A second brick (same density) has dimensions 12 - 18 - and 30. What is the weight of the second brick?
F(x) - c
2.592 kg
16.6666%
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.

32. Describe the relationship between 3x^2 and 3(x - 1)^2
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
Sqrt 12
48
18

33. (12sqrt15) / (2sqrt5) =
The empty set - denoted by a circle with a diagonal through it.
16.6666%
5
(12/2) x (sqrt15 / sqrt5) = 6sqrt3

34. (-1)^2 =
10! / 3!(10-3)! = 120
1
y = (x + 5)/2
2

35. Evaluate (4^3)^2
When the function is not defined for all real numbers -; only a subset of the real numbers.
(a - b)(a + b)
4096
4a^2(b)

36. How many digits are there between the decimal point and the first even digit in the decimal equivalent of 1/[(2^8)(5^3)]
The point of intersection of the systems.
x(x - y + 1)
130pi
0

37. Simplify 9^(1/2) X 4^3 X 2^(-6)?
Factors are few - multiples are many.
A tangent is a line that only touches one point on the circumference of a circle.
1
3

38. Evaluate 4/11 + 11/12
A chord is a line segment joining two points on a circle.
1 & 37/132
1.7
67 - 71 - 73

39. What is the absolute value function?
G(x) = {x}
True
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
An expression with just one term (-6x - 2a^2)

40. Surface area for a cylinder?
Ax^2 + bx + c where a -b and c are constants and a /=0
10! / (10-3)! = 720
3 - -3
2(pi)r^2 + 2(pi)rh

41. What is an exterior angle?
An angle which is supplementary to an interior angle.
(amount of increase/original price) x 100%
4:5
A circle centered at -2 - -2 with radius 3.

42. a^2 - 2ab + b^2
III
10! / 3!(10-3)! = 120
90 degrees
(a - b)^2

43. The slope of a line perpendicular to (a/b)?
61 - 67
72
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
Its negative reciprocal. (-b/a)

44. Which quadrant is the upper left hand?
A reflection about the origin.
3 - -3
II
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15

45. What is the intersection of A and B?
Ax^2 + bx + c where a -b and c are constants and a /=0
1
4a^2(b)
The set of elements found in both A and B.

46. a^0 =
A central angle is an angle formed by 2 radii.
x^(2(4)) =x^8 = (x^4)^2
Its negative reciprocal. (-b/a)
1

47. 1/6 in percent?
16.6666%
An expression with just one term (-6x - 2a^2)
12! / 5!7! = 792
31 - 37

48. Formula to find a circle'S circumference from its radius?
C = 2(pi)r
(amount of increase/original price) x 100%
An arc is a portion of a circumference of a circle.
4:5

49. The larger the absolute value of the slope...
The steeper the slope.
41 - 43 - 47
3sqrt4
The shortest arc between points A and B on a circle'S diameter.

50. If Madagascar'S exports totaled 1.3 billion in 2009 - and 4% came from China - what was the value in millions of the country'S exports to China?
180 degrees
When the function is not defined for all real numbers -; only a subset of the real numbers.
52
4.25 - 6 - 22