Answer:
Mr.Lin's present age is 30 years now. His son is 8 years old now.
Step-by-step explanation:
Let L = Mr.Lin's present age,
S = his son's present age.
First equation is
L + S = 38. (1)
The second equation is
L + 3 = 3*(S+3) (2) ("In three years' time, Mr.Lin will be three times as old as his son.")
From (1), express S = 38-L and substitute it into (2). You will get
L + 3 = 3*((38-L)+3), or
L + 3 = 114 - 3L + 9,
4L = 114 + 9 - 3,
4L = 120,
L = 30.
Answer:
Step-by-step explanation:
Put x = 3, y = 2 and z = 5 to the given expression 
:
<span>1. </span><span>Given numbers
=> 7 centimeters convert to meters
In every 1 meter there are 100 centimeters
=> 7 / 100
=> 0.07
Therefore in 7 centimeters there are 0.07 meters.
7 cm is a whole number while 0.07 m is a decimal number
Scientific Notation of each numbers
=> 7 cm = 7 x 10^0
=> 7 m = 1 x 10^-2
Scientific notation by the way is an expression used by the scientist to make a
large number or very small number easy to handle.
</span>
Answer:
Step-by-step explanation:
Given
Required
Determine the volume
The volume of a cylinder is calculated as thus:
Substitute values for r and h
<em>Hence, the volume of the cylinder is 18312.48mm³</em>
Consider a circle with radius 
centered at some point 
on the 
-axis. This circle has equation
Revolve the region bounded by this circle across the 
-axis to get a torus. Using the shell method, the volume of the resulting torus is
where 
.
So the volume is
Substitute
and the integral becomes
Notice that 
is an odd function, so the integral over ![\left[-\frac\pi2,\frac\pi2\right]](https://tex.z-dn.net/?f=%5Cleft%5B-%5Cfrac%5Cpi2%2C%5Cfrac%5Cpi2%5Cright%5D)
is 0. This leaves us with
Write
so the volume is
