The answer is 21 because 189 divided by 9 is 21
Answer:
The fourth term of the expansion is -220 * x^9 * y^3
Step-by-step explanation:
Question:
Find the fourth term in (x-y)^12
Solution:
Notation: "n choose k", or combination of k objects from n objects,
C(n,k) = n! / ( k! (n-k)! )
For example, C(12,4) = 12! / (4! 8!) = 495
Using the binomial expansion formula
(a+b)^n
= C(n,0)a^n + C(n,1)a^(n-1)b + C(n,2)a^(n-2)b^2 + C(n,3)a^(n-3)b^3 + C(n,4)a^(n-4)b^4 +....+C(n,n)b^n
For (x-y)^12, n=12, k=3, a=x, b=-y, and the fourth term is
C(n,3)a^(n-3)b^3
=C(12,3) * x^(12-3) * (-y)^(3)
= 220*x^9*(-y)^3
= -220 * x^9 * y^3
In terms of its radius 
, the volume of the balloon is
The diameter 
is twice the radius, so that in terms of its diameters, the balloon's volume is given by
Differentiate both sides with respect to time 
:
The diameter increases at a rate of 
. When the diameter is 
, we have
or about 23,562 cc/min (where cc = cubic centimeters)
When a tangent line (13.5 cm) and a secant (lines x + 8.45 cm) intersect then:
tangent line^2 = 8.45 * (8.45 + x)
13.5^2 = 71.4025 + 8.45 x
182.25 -71.4025 = 8.45x
8.45 x = 110.8475
x = 13.1180473373
x = 13.1 (rounded)
Source:
1728.com/circangl.htm
