(d)
Note that
V
5
IR
gives 12
5
2
R
, so
R
5
6 ohms. Now
substitute the known values into the equation in (c).
1
5
2
}
d
d
R
t
} 1
6
1
2}
1
3
}
2
3
5
2
}
d
d
R
t
}
}
d
d
R
t
} 5 }
3
2
}
ohms/sec
R is changing at the rate of
}
3
2
}
ohms/sec. Since this
value is positive,
R
is increasing.
8.
Step 1:
r
5
radius of plate
A
5
area of plate
Step 2:
At the instant in question,
}
d
d
r
t
} 5
0.01 cm/sec,
r
5
50 cm.
Step 3:
We want to find
}
d
d
A
t
}
.
Step 4:
A
5
p
r
2
Step 5:
}
d
d
A
t
} 5
2
p
r
}
d
d
r
t
}
Step 6:
}
d
d
A
t
} 5
2
p
(50)(0.01)
5
p
cm
2
/sec
At the instant in question, the area is increasing at the rate
of
p
cm
2
/sec.
9.
Step 1:
l
5
length of rectangle
w
5
width of rectangle
A
5
area of rectangle
P
5
perimeter of rectangle
D
5
length of a diagonal of the rectangle
Step 2:
At the instant in question,
}
d
d
l
t
}52
2 cm/sec,
}
d
d
w
t
} 5
2 cm/sec,
l
5
12 cm,
and
w
5
5 cm.
Step 3:
We want to find
}
d
d
A
t
}
,
}
d
d
P
t
}
, and
}
d
d
D
t
}
.
Steps 4, 5, and 6:
This is the end of the preview. Sign up
to
access the rest of the document.
This note was uploaded on 10/05/2011 for the course MAC 1147 taught by Professor German during the Spring '08 term at University of Florida.
 Spring '08
 GERMAN

Click to edit the document details