DAT Destroyer QR Flashcards
What does the sin (2x) =
2 sin x cos x
how do you get rid of a square root in the denominator
you multiply the whole thing by the conjugate of the denominator
What do you do for a negative exponent 3^-3
you do the inverse of the thing
1/ 3^3
What do you do for a fraction exponent 9^3/2
- you move the bottom number as a root
if the bottom number is 2 you do the square root
if the bottom number is 3 you do the cube root - and you leave the top as an exponent of the new rooted base
9^3/2 = (square root of 9)^3 9^2/3 = (cube root of 9)^2
If you have 8 horses, how many ways can they finish a race in first, second, third
n! / (n-r)!
8! / (8-3)! = 8x7x6
Use this when order matters!!!
there are 12 people, how many different groups of three can be made
n! / r! x (n-r)!
12! / 3! x 9! = 12x11x10 / 3x2x1
Use this when order doesn’t matter
What is the equation for simple interest
I = Prt
Is 1 a prime number?
nope
what is the sum of the internal angles of a convex polygon equation
sum of the angles, s = (n-2)(180)
what is the secret to this problem
- 625 x 10^5
- —————— - 189 x 10^3
you can round to get 3.6/1.2 = 3x10^2
what is the secret to this problem
jane wants to run 25 miles in 5 days. she wants to run one more mile everyday than she did the previous day. How many miles must she run the first day
x + (x+1) + (x+2) + (x+3) + (x+4) = 25
5x + 10 = 25
x=3
what does 2(sinx*cosx) =
sin 2x
what is the discriminant of a quadratic equation
the part under the square root
B^2 - 4ac
what happens when the descriminant is a positive perfect square
the roots are real, rational, and distinct
what happens when the discriminant of a square root is a positive non-perfect square
the roots are real, irrational, and disticnt