The paraboloid meets the x-y plane when x²+y²=9. A circle of radius 3, centre origin.
<span>Use cylindrical coordinates (r,θ,z) so paraboloid becomes z = 9−r² and f = 5r²z. </span>
<span>If F is the mean of f over the region R then F ∫ (R)dV = ∫ (R)fdV </span>
<span>∫ (R)dV = ∫∫∫ [θ=0,2π, r=0,3, z=0,9−r²] rdrdθdz </span>
<span>= ∫∫ [θ=0,2π, r=0,3] r(9−r²)drdθ = ∫ [θ=0,2π] { (9/2)3² − (1/4)3⁴} dθ = 81π/2 </span>
<span>∫ (R)fdV = ∫∫∫ [θ=0,2π, r=0,3, z=0,9−r²] 5r²z.rdrdθdz </span>
<span>= 5∫∫ [θ=0,2π, r=0,3] ½r³{ (9−r²)² − 0 } drdθ </span>
<span>= (5/2)∫∫ [θ=0,2π, r=0,3] { 81r³ − 18r⁵ + r⁷} drdθ </span>
<span>= (5/2)∫ [θ=0,2π] { (81/4)3⁴− (3)3⁶+ (1/8)3⁸} dθ = 10935π/8 </span>
<span>∴ F = 10935π/8 ÷ 81π/2 = 135/4</span>
Answer:
Step-by-step explanation:
n and d are the number of nickels and dimes, respectively.
"there are 20 coins"
n+d = 20
d = 20-n
"total value is $1.40"
0.05n + 0.10d = 1.40
0.05n + 0.10(20-n) = 1.40
-0.05n + 2 = 1.40
0.05n = 0.6
n = 12
d = 20-m = 8
Answer:
the answer is C
Step-by-step explanation:
The option c is the answer because
2p=p (1.07)^x
2=1.07^x
Solve for x
X=log(2)÷log(1.07)
x=10 years the amount will be doubled after 10 years
But your option says the investment will (more) than double with (12) years
So it's correct
