Answer:
c=80
Step-by-step explanation:
Based on my reading the critical damping occurs when the discriminant of the quadratic characteristic equation is 0.
So let's see that characteristic equation:
20r^2+cr+80=0
The discriminant can be found by calculating b^2-4aC of ar^2+br+C=0.
a=20
b=c
C=80
c^2-4(20)(80)
We want this to be 0.
c^2-4(20)(80)=0
Simplify:
c^2-6400=0
Add 6400 on both sides:
c^2=6400
Take square root of both sides:
c=80 or c=-80
Based on further reading damping equations in form
ay′′+by′+Cy=0
should have positive coefficients with b also having the possibility of being zero.
Answer:
Step-by-step explanation:
The given equation is
We take logarithm of both sides to base 10.
We expand the brackets to get;
Group similar terms;
To the nearest hundredth.
If you multiply 48cm times 15cm,you get 720cm.Which would leave you with 60 left because 780 minus 720 equals 60.The height of the other base is 60cm.
Answer:9 cm by 9cm
Step-by-step explanation: 3*3=9
30b + 100u = 900
5b + 25u = 200....multiply by -6
------------------
30b + 100u = 900
-30b - 150u = - 1200 (result of multiplying by -6)
------------------add
-50u = - 300
u = 6 <== upgrated phones sold
30b + 100u = 900
30b + 100(6) = 900
30b + 600 = 900
30b = 900 - 600
30b = 300
b = 10 <== basic phones sold
