5.7.6 Fungsi Trigonometri, SPM Praktis (Kertas 1)


5.7.6 Fungsi Trigonometri, SPM Praktis (Kertas 1)

Soalan 15:
Buktikan identiti 2 kos2A+1 =se k 2 A

Peneyelesaian:
Sebelah kiri 2 kos2A+1 = 2 ( 2ko s 2 A1 )+1 kos2A=2ko s 2 A1 = 2 2ko s 2 A = 1 ko s 2 A =se k 2 A =Sebelah kanan


Soalan 16:
Buktikan identiti 2tanA 2se k 2 A =tan2A

Peneyelesaian:
Sebelah kiri 2tanA 2se c 2 A = 2tanA 2( tan 2 A+1 ) tan 2 A+1=se c 2 A = 2tanA 1 tan 2 A =tan2A =Sebelah kanan


Soalan 17:
Buktikan identiti tan x + kot x = 2 kosek 2x

Peneyelesaian:
Sebelah kiri,
tan x + kot x
= sinx kosx + kosx sinx = sin 2 x+ko s 2 x kosxsinx = 1 kosxsinx sin 2 x+ko s 2 x=1 = 1 1 2 sin2x sin2x=2sinxkosx 1 2 sin2x=sinxkosx = 2 sin2x =2( 1 sin2x ) =2kosek 2x =Sebelah kanan


Soalan 18:
Buktikan identiti kosxsin2x kos2x+sinx1 = 1 tanx   

Peneyelesaian:
Sebelah kiri kosxsin2x kos2x+sinx1 = kosx2sinxkosx ( 12 sin 2 x )+sinx1 kos2x=12 sin 2 x = kosx( 12sinx ) sinx2 sin 2 x = kosx( 12sinx ) sinx( 12sinx ) = kosx sinx =kotx = 1 tanx Sebelah kanan

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