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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. How to find the diagonal of a rectangular solid?
130pi
4.25 - 6 - 22
A term is a numerical constant or the product (or quotient) of a numerical constant and one or more variables. (3x - 4x^2 and 2a/c)
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).

2. Whats the difference between factors and multiples?
Factors are few - multiples are many.
4a^2(b)
A= I (1 + (r/c))^tC - where I is the investment - C is the number of times compounded annually - and t is the number of years.
1

3. When does a function automatically have a restricted domain (2)?
53 - 59
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
A circle centered on the origin with radius 8.
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.

4. In a triangle inscribed inside a circle - where the diameter is one side of the triangle - which angle is largest?
(base*height) / 2
F(x) + c
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
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

5. What is the absolute value function?
75:11
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
G(x) = {x}
(base*height) / 2

6. A number is divisible by 6 if...
C = (pi)d
The sum of digits is divisible by 9.
11 - 13 - 17 - 19
Its divisible by 2 and by 3.

7. A number is divisible by 3 if ...
Triangles with same measure and same side lengths.
An expression with just one term (-6x - 2a^2)
9 : 25
The sum of its digits is divisible by 3.

8. When the 'a' in a parabola is positive....
The curve opens upward and the vertex is the minimal point on the graph.
23 - 29
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
Indeterminable.

9. a^2 - b^2 =
1/(x^y)
(a - b)^2
(a - b)(a + b)
No - the input value has exactly one output.

10. Factor x^2 - xy + x.
x(x - y + 1)
413.03 / 10^4 (move the decimal point 4 places to the left)
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)

11. What is a central angle?
90
A central angle is an angle formed by 2 radii.
16.6666%
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.

12. What is an arc of a circle?
An arc is a portion of a circumference of a circle.
C = 2(pi)r
20.5
180

13. Which quadrant is the lower left hand?
12sqrt2
III
11 - 13 - 17 - 19
Cd

14. Which quadrant is the upper right hand?
130pi
I
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
70

15. 200 <_ x <_ 300. How many values of x are divisible by 5 & 8?
A term is a numerical constant or the product (or quotient) of a numerical constant and one or more variables. (3x - 4x^2 and 2a/c)
3
8
75:11

16. Simplify 4sqrt21 X 5sqrt2 / 10sqrt7
2sqrt6
F(x-c)
Yes. [i.e. f(x) = x^2 - 1
1

17. A cylinder has a surface area of 22pi. If the cylinder has a height of 10 - what is the radius?
3
N! / (n-k)!
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
1

18. 5/6 in percent?
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
Area of the base X height = (pi)hr^2
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
83.333%

19. Formula for the area of a sector of a circle?
1
Yes. [i.e. f(x) = x^2 - 1
Sector area = (n/360) X (pi)r^2
F(x-c)

20. Formula to find a circle'S circumference from its diameter?
C = (pi)d
1.0843 X 10^11
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
1/2 times 7/3

21. What are the integers?
... the square of the ratios of the corresponding sides.
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
All numbers multiples of 1.
When the function is not defined for all real numbers -; only a subset of the real numbers.

22. What is the 'Restricted domain of a function'?
A central angle is an angle formed by 2 radii.
6
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
When the function is not defined for all real numbers -; only a subset of the real numbers.

23. Solve the quadratic equation ax^2 + bx + c= 0
Its negative reciprocal. (-b/a)
1
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
x^(4+7) = x^11

24. What is the 'Range' of a series of numbers?
Arc length = (n/360) x pi(2r) where n is the number of degrees.
4096
10! / 3!(10-3)! = 120
The greatest value minus the smallest.

25. What is the percent formula?
A set with no members - denoted by a circle with a diagonal through it.
.0004809 X 10^11
Part = Percent X Whole
The third side is greater than the difference and less than the sum.

26. What does the graph (x+2)^2 + (y+2)^2 = 9 look like?
(b + c)
x^(6-3) = x^3
An expression with just one term (-6x - 2a^2)
A circle centered at -2 - -2 with radius 3.

27. x^(-y)=
1/(x^y)
x= (1.2)(.8)lw
(b + c)
x^(6-3) = x^3

28. What are 'Supplementary angles?'
3
An arc is a portion of a circumference of a circle.
Two angles whose sum is 180.
y = 2x^2 - 3

29. Evaluate and write as a mixed number: 2/7 - 3/21 + 2 & 4/14
2 & 3/7
x^(6-3) = x^3
Part = Percent X Whole
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

30. What is the surface area of a cylinder with radius 5 and height 8?
130pi
41 - 43 - 47
2.592 kg
2^9 / 2 = 256

31. 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?
Pi is the ratio of a circle'S circumference to its diameter.
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
9 : 25
The set of input values for a function.

32. To multiply a number by 10^x
.0004809 X 10^11
Move the decimal point to the right x places
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
28. n = 8 - k = 2. n! / k!(n-k)!

33. Can you add sqrt 3 and sqrt 5?
8
No - only like radicals can be added.
A central angle is an angle formed by 2 radii.
A = I (1 + rt)

34. Formula of rectangle where l increases by 20% and w decreases by 20%
16.6666%
x= (1.2)(.8)lw
71 - 73 - 79
The steeper the slope.

35. 0^0
(p + q)/5
12! / 5!7! = 792
23 - 29
Undefined

36. (6sqrt3) x (2sqrt5) =
10! / 3!(10-3)! = 120
IV
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
A grouping of the members within a set based on a shared characteristic.

37. 413.03 x 10^(-4) =
413.03 / 10^4 (move the decimal point 4 places to the left)
F(x-c)
Angle/360 x (pi)r^2
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a

38. Which quadrant is the upper left hand?
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
II
Sector area = (n/360) X (pi)r^2

39. What is the coefficient of the x^2 term in the product of (x + 1)(x + 2)(x -1)?
6
1
2
4096

40. 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?
2.592 kg
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
180
(b + c)

41. What is the maximum value for the function g(x) = (-2x^2) -1?
The curve opens upward and the vertex is the minimal point on the graph.
1
180 degrees
3

42. What is the ratio of the surface area of a cube with an edge of 10 to the surface area of a rectangular solid with dimensions 2 - 4 - and 6?
A = pi(r^2)
Undefined - because we can'T divide by 0.
75:11
The shortest arc between points A and B on a circle'S diameter.

43. What is the 'Range' of a function?
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
The set of output values for a function.
Divide by 100.
...multiply by 100.

44. If 10800 is invested at a simple interest rate of 4% - what is the value of the investment after 18 months?
$11 -448
The union of A and B.
27^(-4)
The longest arc between points A and B on a circle'S diameter.

45. A triangle is inscribed in a semi circle with legs 5 and 12. What is the circumfermence of the semicircle?
7 / 1000
The sum of digits is divisible by 9.
12.5%
13pi / 2

46. x^2 = 9. What is the value of x?
55%
4725
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
3 - -3

47. 10^6 has how many zeroes?
$3 -500 in the 9% and $2 -500 in the 7%.
6
Its negative reciprocal. (-b/a)
The set of elements found in both A and B.

48. 40 < all primes<50
The third side is greater than the difference and less than the sum.
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
28. n = 8 - k = 2. n! / k!(n-k)!
41 - 43 - 47

49. Legs 6 - 8. Hypotenuse?
A chord is a line segment joining two points on a circle.
The two xes after factoring.
The set of output values for a function.
10

50. What is the 'union' of A and B?
An infinite set.
1.0843 X 10^11
The set of elements which can be found in either A or B.
2sqrt6