Math Formulas Flashcards
What are distinct prime factors?
prime factors that together multiply to the listed number but are not repeated
When would you use the picking number strategies?
Picking numbers do not use modular arithmatic on GRE (problem solving avoid -1, 0, 1). trying to pick different numbers that demonstrate thtat the information provided could produce different results (different relationships between two problems). Pciking numbers w/ special properties will often force there to be a difference (pos. vs. neg., odd vs. even, small vs. big, -1<0<1 1,0,1 only use these for quantitative comparison questions). if you are unable to produce different results for the comparison characteristiscs select the correct choice and move on
• pcik numbers for questions w/ variables in the question stem, choose numbers that follow rules and are easyto work with, choose numbers that follow rules and easy to work with. Multiple choice: if answer coices are numbers, any choice w/ right result sis correct, if answer choices are algebraic expressions, check every one; when picking numbers in quantittave comparison questions, force different results by choosing a variety of numbers
How do you back solve?
Backsolving: working “backward from an answer choice to determine whether it agrees w/ the information in the question stem.
• not work w/ quantitiative comparison, numeric entry questions, could work for data interpretation.
backsolving. have numbers in order. if manageable answer choice (B or D start point) likely answer.
What is the kaplan method?
Analyze the question (figure out the strategy), identify the task (what is the question asking exactly), choose a strategy (pick numbers, backsolve, do traditional math, take a strategic guess), confirm answer (check math and confirm answer to what questions ask).
What are reminders?
• reminders mean that goes into it once and what is left over
What is the kaplan method for problem solving?
- Analyze the question.
- Identify the task.
- Approach strategically.
• Do the math
• Pick numbers
• Backsolve
• Make a strategic guess - Confirm your answer.
What is the kaplan method for quantitative comparison?
- Analyze the centered information and quantities.
- Approach strategically.
• Compare, don’t calculate
• Compare quantities piece by piece
• Make one quantity look like the other
• Do the same thing to both quantities
• Pick numbers
• Simplify the centered information
• Suspect (D) is the answer
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What are the properties of a slope?
• slope=rise/run=change in y/change in x. going up is positive slope any line going down is negative slope. straight up is undefined slope. slope=y2-y1/x2-x1. y=mx+b
What are the volume and surface area of a cylinder?
• volume of a cylinder=(pi)r^2h; SA=2(pi)r^2+2(pi)rh
What is the volume and surface area of a rectangle?
• rectangles: surface area of uniform solids=sum of area of all sides. SA=2(lw)+2(lh)+2(wh). volume of uniform solids=area of base times height; volume=lxwxh
What is the circumference and area of a circle?
circumference=pid or 2pir. area=pir2. c=dpi
What are the angles and lengths of an isosceles triangle?
45:45:90 isosceles x: x: x square root of 2
What are the angles and lengths of a triangle?
30:60”90 x: x square root of three: 2x
What is the pythagreum theorem?
a2+b2=c2
What are the most common pythagreum theorem triangles?
. 3:4:5 ratios, 5:12:13.
What is the strategy of comparing two different shapes?
• doing shapes you subtract the area of the big shape from the area of the little shape
What is the radius and diameter?
radius is center to edge. diameter- directly through center and touches both edges.
How do you calculate the number of sides of a figure or the angles of a multi-sided angle?
• Interior angles or sum of interior angles. 180 (n-2) n=number of sides of figure
What are parallelograms and how do you find their area?
• parallelogram- any quadrilateral where the sides across from each other are parallel. sides across from eachother angle. angles directly across are also the same. area is base times height so long as its perpendicular. rectangle and square are parallelograms.
What is the triangle inequality theorem?
• triangle inequality theorem if third side equaled the differene between the two sides third side has to be longer than the difference. third side has to be less than the sum bigger than the difference and smaller than the sum
What is the perimeter?
• perimeter length of all sides of shape
What is the area?
• area measurement of space inside shape measures two dimensional so squared. 1/2bh
What are the interior angles of a triangle?
• interior angles of triangle all add up to 180
What is special about an equilateral triangle?
• equilateral triangle all interior angles are the same, same as sides
What are the angles of different locations?
- supplementary angles angles that add up to 180 degrees.
* angles in same position or are across from each other are the same degree
What are the multiplication principles?
ο Multiplication principles- combining multiple possibilities. Given the number of choices as the base and the number of possibilities as the power
What do you apply the slot strategy?
• apply the slot strategy to permutations questions to figure out how many ways things can be ordered. make a list of slots for the number of possibilities left for each from left to right? multiply all of the possibilities for each slot aka a factorial.
What is the permutation formula?
• nCk=n!/k!(n-k)! n=the total number of items how many items choosing from. k=subgroup how many are we trying to chose from that larger group. can do 6.4x5.3x4.2x3/1 set up permutation w/ slots then divide by the slots factorial.
What are overlapping sets?
• overlapping sets= group1+ group 2+neither-both
What is the average?
• average=sum of values/number of values
What is the teeter totter?
• balancing method draw teeter totter. Teeter Totter two numbers on one side w/ average in center and choice the number that would be holding it up on the other side away from the center number and compare w/out calculating looking at the numbers left that fill that.
What is frequency?
• frequency multiplying scores by their frequency and then divide by the total frequency or total number
What is the zeroing strategy?
• zeroing strategy- replace first number w/ a zero and increase up for each of the next options add all those to make it easier then add the average w/ the adjusted values to the first number seet and it is the new average