Tuesday, May 29, 2012
May 29, 2012 – Powers in the Quant Section in GMAT
While I have been working on the quant section, POWERS is one of the topics that is tested and on which questions can be expected. Below are a few pointers to keep in mind with regards to the Powers that I have been able to recollect and which I have read in a few quant related articles --:
1. Keep in mind the properties of Powers (Addition, Subtraction, Multiplication)
2. 0 is an EVEN number
3. An power is always , whether the is positive or negative.
(-2)^2 = 4 and (2)^2 = 4
4. An power the base's original sign.
(-2)^3 = -8 and (2)^3 = 8
5. and powers with the :
: add or subtract the exponents
: x3 + x5 ≠ x8
: extract the highest common factor.
: x3 + x5 = x3(1+x2)
6. If you're not sure that you factored the expression correctly, check that re-expanding the brackets does return to the original expression. This is a method to cross-check and should be used if you have time and are unsure of your answer
7. Like terms (same base and same exponent) can always be added/subtracted:
6a2 + 3a2 = 9a2
8. Whenever one encounters an in the GMAT, it only represents the solution. Which is why x in the quadratic equation x^2-4=0 will equal ±2, but if it is stated as only √4 then it will equal 2 alone. By EVEN Root, the statement refers to square root or 4th root, 6th root and so on.
9. In other words, both positive and negative roots must be considered if , as part of solving an equation, for example.
10. If the root sign is , it signifies only the positive root (This is a mathematical convention).