av Sean Leow 13 år siden
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R-formula and Trigonometry(Sean Group)
R-formula and Trigonometry(Sean Group)
R-formula
Tan alpha = b/a
Where R=Square root of Asquare + b Square
acosx+bsinx=Rcos(x-a)/ acosx-bsinx=Rcos(x+a)
asinx+bcosx=R sin(x+a)/ asinx-bcosx= Rsin(x-a)
Double angle formulae
tan2A=2tanA/1-tansquare A
cos2A=cos square A- sin square A/ 2cos square A- 1/ 1-2sin square A
sin2A=2sinAcosA
Addition formulae
cos(a-b)=cosacosb+sinasinb
tan(a-b)=tana-tanb/1+tanatanb
tan(a+b)=tana+tanb/1-tanatanb
cos(a+b)=cosacosb-sinasinb
sin(a-b)=sinacosb-cosasinb
sin(a+b)=sinacosb+cosasinb
trigo ratio
tan60=square root 3
tan45=1
tan30=1/squareroot 3
cos60=1/2
cos45=1/squareroot2
cos30=squareroot 3 /2
sin60=squareroot 3 /2
sin45=1/square root 2
sin30=1/2
Trigo identites
sin square x+ cos sqaure x=1
1+tan square= sec square
cosecx=1/sinX
1+cot square = cosec square
secx=1/cosx
Cotx=1/tanx
Tanx= Opposite/adjacent
4th quadrant cosine positive
3rd quadrant tangent positive
2nd quadrant sine positive
1st quadrant all positive
1degree=π/180degree
1 radian=180degree/π
Cosx=Adjacent/hypotenus
Sinx=Opposite/Hypotenus