buktikan indentitas ! 1.COS kuadrat \alpha [/tex] (1+tan kuadrat alpha ) = 1 2.COS alpha (1- t tan alpha) = cos alpha - sin alpha 3.tan alpha (1 + cos alpha)

mis : alpha = β

1.
cos²β ( 1 + tan² β) = 1
= cos²β + cos²β*sin²β/cos²β
= cos² β + sin²β
= 1
(Terbukti)


2.
cos β (1-tan β ) = cosβ - sin β
= cos β - cosβ(tanβ)
= cos β - cosβ (sinβ/cosβ)
= cos β - sin β
(Terbukti)

3.
tan β (1 + cos β) = tan β + sin β
= tan β +cosβ (sinβ/cosβ)
= tan β + sin β
(Terbukti)

4.
sinβ cosβ (tanβ + cotβ) = 1
= sinβ cosβ(tanβ) + sinβ cosβ (cotβ)
= sinβ * sinβ + cosβ * cosβ
= sin² β + cos² β
= 1
(Terbukti)

5.
soal tidak jelas