Monday, January 18, 2010

Taylor Reflection #22

I know all the formulast we have had to memorize

they are

Sine and Cosine Sum/Difference Formulas

cos(alpha+/-beta)=cos alpha cos beta-/+sin alpha sin beta )
sin(alpha+/- beta)=sin alpha cos beta +/-cos alpha sin beta
sin x+sin y=2sin(x+y/2)cos(x-y/2)
sin x-sin y=2cos(x+y/2)sin(x-y/2)
cos x+cos y= 2cos(x+y/2)cos(x-y/2)
cos x-cos y=-2sin(x+y/2)sin(x-y/2)



Tangent Sum/Difference Formulas

tan(alpha+beta)=tan alpha+tan beta/1-tan alpha tan beta
tan alpha-beta=tan alpha-tan beta/1+tan alpha tan beta




Double-Angle/Half-Angle Formulas

sin 2 alpha=2sin alpha cos alpha
cos 2 alpha=cos^2 alpha-sin^2 alpha=1-2sin^2 alpha=2cos^2 alpha-1
tan 2 alpha=2tan alpha/1-tan^2 alpha
sin(alpha/2)=+/-sqrt(1-cos alpha/2) cos(alpha/2)= +- sqrt(1+cos alpha/2)
tan(alpha/2)= +- sqrt(1-cos alpha/1+cos alpha)=sin alpha/1+cos alpha= 1-cos alpha/sin alpha\



sin=y/r
cos=x/r
tan=y/x
cot=x/y
sec=r/x
csc=r/y



Trig Chart:


sin0=0
cos0=1
tan0=undefined
sec0=1
cot0=0

30°
sinπ/6=1/2
cosπ/6=√3/2
tanπ/6=√3/3
cscπ/6=2
secπ/6=2 √3/3
cotπ/6=√3

45°
sinπ/4=√2/2
cosπ/4=√2/2
tanπ/4=1
cscπ/4=√2
secπ/4=√2
cotπ/4=1

60°
sinπ/3=√3/2
cosπ/3=1/2
tanπ/3=√3
cscπ/3=2 √3/3
secπ/3=2
cotπ/3=√3/2

90°
sinπ/2=1
cosπ/2=0
tanπ/2=undefined
cscπ/2=1
secπ/2=undefined
cotπ/2=0




Reciprocal Relationships:

cscΘ=1/sinΘ
secΘ=1/cosΘ
cotΘ=1/tanΘ



Relationships with Negatives:

sin -Θ= -sinΘ and cos -Θ= -cosΘ
csc -Θ= -cscΘ and sec -Θ= -secΘ
tan -Θ= -tanΘ and cot -Θ= -cotΘ



Pythagorean Relationships:

sin²Θ+cos²Θ=1
1+tan²Θ=sec²Θ
1+cot²Θ=csc²Θ



Cofunction Relationships:

sinΘ=cos(90°-Θ) and cosΘ=sin(90°-Θ)
tanΘ=cot(90°-Θ) and cotΘ=tan(90°-Θ)
secΘ=csc(90°-Θ) and cscΘ=sec(90°-Θ)





and for the most part i can work the equations
the two types of equations i am having trouble with are

A: the ones where is asks you to find something when it is _<_<_

and

B: the ones where it calls for the use of the chapter eight

i get a little lost in translation of the formulas with the new formulas
so if anyone knows any tricks for these that would be great

1 comment:

  1. Ok so for your question on A, the _<_<_ thing is basically sayin where your points are gonna be in which quadrant. like if it says 0 degress < x < 180 degrees, that means you are looking in quadrants 1 and 2. If the trig function is negative like if its cos(-140) then it will be in quadrant 2 and if it is cos(60) then it will be in quadrant 1.

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