Answer:
volume of cone = 12.56 cubic units
Step-by-step explanation:
Volume of cone = 1/3 π r² h
r = 2
h = 3
then
V= 1/3 3.14 * (2) ² 3
= 12.56 cubic units
Selection D is the equivalent form of the given expression.
_____
The nominal annual interest rate in this problem is 40%. If it were compounded half-yearly, the formula would be x(1.2)^(2t) or x(1.44)^t. Apparently, this problem is more concerned with the equivalent form of the expression than it is with half-yearly compounding.
Answer:
2t
Step-by-step explanation:
The expressions are not the same because different terms are negative. We can visualize the difference by rewriting the expressions as 13t + (-2t) and (-13t) + 2t. In the first expression, 13t-2t, the 2t is negative because it is being subtracted, and subtracting a number is the same as adding a negative.
Answer:
y(t) = c₁ e^(-1/2 t) cos(√3/2 t) + c₂ e^(-1/2 t) sin(√3/2 t) + 1
Step-by-step explanation:
y" + y' + y = 1
This is a second order nonhomogenous differential equation with constant coefficients.
First, find the roots of the complementary solution.
y" + y' + y = 0
r² + r + 1 = 0
r = [ -1 ± √(1² − 4(1)(1)) ] / 2(1)
r = [ -1 ± √(1 − 4) ] / 2
r = -1/2 ± i√3/2
These roots are complex, so the complementary solution is:
y = c₁ e^(-1/2 t) cos(√3/2 t) + c₂ e^(-1/2 t) sin(√3/2 t)
Next, assume the particular solution has the form of the right hand side of the differential equation. In this case, a constant.
y = c
Plug this into the differential equation and use undetermined coefficients to solve:
y" + y' + y = 1
0 + 0 + c = 1
c = 1
So the total solution is:
y(t) = c₁ e^(-1/2 t) cos(√3/2 t) + c₂ e^(-1/2 t) sin(√3/2 t) + 1
To solve for c₁ and c₂, you need to be given initial conditions.
