Angel's Guide to Those Pesky Trigonometric Functions and
Identites
- A great site for more information: Eric's Treasure Trove of
Mathematics (just about anything you can think of)
- Trig without
tears
- Another GREAT Site for a lot of math questions: Dave's Math Tables (pretty comprehensive at
entry level)
- Integrals:
TOI (table of integrals)
|
A site that lets you enter integrals to
solve! <-------**
- Constants: Physical
Constants (a few) | More
Physical Constants Here (a few more) |
NIST's
Site of Physical Constants (lots - by name)
tan A = cot(90-A)
cot A = tan(90-A)
sec A = csc(90-A)
csc A = sec(90-A)
tan(-A) = - tan A
cot(-A) = - cot A
sec(-A) = sec A
csc(-A) = - csc A
sin² A + cos² A = 1
tan² A + 1 = sec² A
cot² A + 1 = csc² A
cos(A+B) = cosA cosB - sinA sinB
sin(A+B) = sinA cosB + cosA sinB
cos(A-B) = cosA cosB + sinA sinB
sin(A-B) = sinA cosB - cosA sinB
tan(A+B) = (tanA + tanB) / (1 - tanA tanB)
tan(A-B) = (tanA - tanB) / (1 + tanA tanB)
sin(2A) = 2 sinA cosA
cos(2A) = cos² A - sin² A = 2 cos² A - 1 = 1 - 2
sin² A
tan(2A) = 2 tanA / (1 - tan² A)
"Proof":
sin(2A) = sin(A+A) = sinA cosA + cosA sinA = 2 sinA cosA
cos(2A) = cos(A+A) = cosAcosA - sinA sinA = cos² A - sin² A
sin(B/2) = 1 sqrt[(1 - cos B)/2]
cos(B/2) = 1 sqrt[(1 + cos B)/2]
tan(B/2) = (1 - cos B) / sin B = sin / (1 + cos B)
a / sinA = b / sinB = c / sinC
cos C = (a² + b² - c²) / 2ab
c² = a² + b² - 2ab cos C
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