436 Formulas and Theorems
f.
∫
√^1
a^2 −x^2
dx=sin−^1
(x
a
)
+C
g.
∫
1
a^2 +x^2
dx=
1
a
tan−^1
(x
a
)
+C
h.
∫
1
x
√
x^2 −a^2
dx=
1
a
sec−^1
∣∣
∣
x
a
∣∣
∣+Cor
1
a
cos−^1
∣∣
∣
a
x
∣∣
∣+C
i.
∫
sin^2 xdx=
x
2
−
sin( 2 x)
4
+C
Note: sin^2 x=
1 −cos 2x
2
and
cos^2 x=
1 +cos(2x)
2
Note: After evaluating an integral, always
check the result by taking the derivative of
the answer (i.e., taking the derivative of the
antiderivative).
- The Fundamental Theorems of Calculus:
∫b
a
f(x)dx=F(b)−F(a),
whereF′(x)=f(x).
IfF(x)=
∫x
a
f(t)dt, thenF′(x)=f(x).
- Trapezoidal Approximation:
∫b
a
f(x)dx
=
b−a
2 n
[
f
(
x 0
)
+ 2 f
(
x 1
)
+ 2 f
(
x 2
)
...
+ 2 f
(
xn− 1
)
+f(xn)
]
- Average Value of a Function:
f(c)=
1
b−a
∫b
a
f(x)dx
- Mean Value Theorem:
f′(c)=
f(b)− f(a)
b−a
for somecin (a,b).
Mean Value Theorem for Integrals:
∫b
a
f(x)dx= f(c)(b−a) for somec
in (a,b).
- Area Bounded by 2 Curves:
Area=
∫x 2
x 1
(f(x)−g(x))dx,
where f(x)≥g(x).
- Volume of a Solid with Known Cross Section:
V=
∫b
a
A(x)dx,
whereA(x)is the cross section.
- Disc Method:
V=π
∫b
a
(f(x))^2 dx, wheref(x)=radius.
- Using the Washer Method:
V=π
∫b
a
(
(f(x))^2 −(g(x))^2
)
dx,
where f(x)=outer radius and
g(x)=inner radius.
- Distance Traveled Formulas:
- Position Function:s(t);s(t)=
∫
v(t)dt
- Velocity:v(t)=ds
dt
;v(t)=
∫
a(t)dt
- Acceleration:a(t)=dv
dt - Speed:
∣∣
v(t)
∣∣