penyelesaian Sin (α+β), con (α+β) dan tan (α+β) jika sin α = 4/5 dan con β = 5/13 , dimana α dan β dikuadran 1
Jawaban Terkonfirmasi
Sin α = 4/5 sin β = 12/13 inget pakai rumus alm. pyhtagoras!!!
cos α = 3/5 cos β = 5/13
tan α = 4/3 tan β = 12/5
sin (α + β) = sin α cos β + cos α sin β
= 4/5 5/13 + 3/5 12/13
= 20/65 + 36/65 = 56/65
cos (α + β) = cos α cos β – sin α sin β
= 3/5 5/13 – 4/5 12/13
= 15/65 – 48/13
= – 33/65
tan (α + β) = tan α + tan β = 4/3 + 12/5 = 56/15 = 56/15 = – 56/33
1 – tan α tan β 1 – 4/3 12/5 1 – 48/15 - 33/15