Answer:
1287
Step-by-step explanation:
Number of people in elevator , n = 8
Number of floors, r = 6
Since they all look alike, arrangement doesn't matter, the we use combination :
(n+r-1 r - 1) = (8+6-1 C 6-1) = 13C5
Recall:
nCr = n! / (n-r)!r!
13C5 = 13! / (13-5)!5!
13C5 = 13*12*11*10*9 / 5*4*3*2*1
= 1287
Since only one person can finish in first place, one in second, etc., the total number of placers is 12x11x10, or 1320 different ways the 12 racers can finish 1st, 2nd and 3rd....
☺☺☺☺
Answer:
Step-by-step explanation:
sin x=a+b
cos x=a-b
sin²x+cos²x=(a+b)²+(a-b)²=2a²+2b²
or 2a²+2b²=1
a²+b²=1/2 which is constant for all values of x
(ii)
The solution/answer to your question is -20 y
Answer:
x2 +8x +4y +4 = 0
4y= -x2 -8x -4y = -.25*x^2 -2x -1
a = -.25b = -2c = -1
x position of vertex:
h = -b / 2a
h = 2 / 2*-.25h = 2 / -.5h = -4
y position of vertex:
k = ah^2 + bh + ck = -.25*-4^2 + -2*-4 + -1k = -4 +8 -1k = 3
VERTEX = (-4, 3)*
x value of focus =x value of vertex = -4
y value of focus =(1 (-b^2 -4ac)) / 4a
a = -.25 b = -2 c =-1
y value = (1 (-4 -4*-.25*-1)) / 4*-.25
y value = (1 (-4 -4*-.25*-1)) / -1
y value = (1 -4 +1) / -1y value = (-2 / -1)y value = 2
focus value = (-4, 2)
Answer is the last one.
