Recitation #3
Inverse of
-
Tangent Function
arctan()
if
x >0
-arctan ( * ) +
if X10 and
-arctan()-i
if Xc0 and
y20
y
atan(*
)
tanG ERR
stanzly x)
,
·
&
N
N
X)0
*
-
Example Compute
9) Ai
A
=
=
E
Az
,
A & 0
=
=
the
() =
=
,
Ac
0
=
=
T
=
600
or
=
=
or
-
A
=
0
=
A?
+
Az
atan2(Az A
=
,
=
-
+
- =
Azzo
arctan (E)
0 arctan
1
arcta()
=
)
if tota()
if A , 0
&
=
,
,
0
=
=
5
1
arcta)-i
8 -2400
1
-
+
0
"T
if A Co
AF
( =
A
=
Y
:
1
arcton()
b) A = 't
following
cases
z
A
0
in
X
*o
A
:
&
+
Ao
()
-
iT
i
Example The free response of the damped single dof system with
:
recorded to be
of the
and
the stiffness is
are
measured to be 9
.
and
1 mm · Calculate the
↳ x(t)
Displacement
=
-
tz
and
to
coefficient
X (t) Ae
,
Fin
friction-free
,
3w-in (wa
t , = +z + T
X(t)
T)
4 +2 + 82
Cor 2 m
=
=
damping
=
x(t +
S
f
Ikg is
performed
.
surface
=
of
figure below A static deflection test is
determined to be 1 5X103 N/m. The displacement at t
form in the
/
S In
mass
a
2
=
(1 Sx183) (2)
.
109 54
.
8
=
*Itin[Omm]-S
In
2 1972
9
.
f
=
-
4+ + 2 1972
.
J =
c
=
+
c
(0 33)(109 54)
.
C
=
.
36 15
.
kg/s
=
y Gr
.
=
0 33
.
=
21
o)
+ +