436 Formulas and Theorems
f.∫
√^1
a^2 −x^2dx=sin−^1(x
a)
+Cg.∫
1
a^2 +x^2
dx=1
a
tan−^1(x
a)
+Ch.∫
1
x√
x^2 −a^2dx=1
a
sec−^1∣∣
∣
x
a∣∣
∣+Cor1
a
cos−^1∣∣
∣a
x∣∣
∣+Ci.∫
sin^2 xdx=
x
2−
sin( 2 x)
4+C
Note: sin^2 x=
1 −cos 2x
2
andcos^2 x=
1 +cos(2x)
2Note: 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
af(x)dx=F(b)−F(a),whereF′(x)=f(x).IfF(x)=∫xaf(t)dt, thenF′(x)=f(x).- Trapezoidal Approximation:
∫b
af(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∫baf(x)dx- Mean Value Theorem:
f′(c)=f(b)− f(a)
b−a
for somecin (a,b).Mean Value Theorem for Integrals:
∫baf(x)dx= f(c)(b−a) for somecin (a,b).- Area Bounded by 2 Curves:
Area=∫x 2x 1(f(x)−g(x))dx,where f(x)≥g(x).- Volume of a Solid with Known Cross Section:
V=
∫baA(x)dx,whereA(x)is the cross section.- Disc Method:
V=π∫ba(f(x))^2 dx, wheref(x)=radius.- Using the Washer Method:
V=π∫ba(
(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)
∣∣