prove the following identity : 1.sin alpha cos (90°- alpha) +cos alpha sin (90°- alpha) = 1 2. tan² Alpha + 1 = sec² alpha ; ctg² alpha + 1 = cosec 3. tan (90°
Matematika
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prove the following identity : 1.sin alpha cos (90°- alpha) +cos alpha sin (90°- alpha) = 1 2. tan² Alpha + 1 = sec² alpha ; ctg² alpha + 1 = cosec 3. tan (90° - alpha) + cos alpha sin (90° - alpha) ctg alpha = 2 4. tg²alpha - sin² alpha = tg² alpha x sin² alpha 5. cos⁴ alpha (1 + tg⁴ alpha) = 1 - 2 sin² alpha cos² alpha
1 Jawaban
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1. Jawaban Anonyme
alpha = a
1][
sin a . cos (90° - a) + cos a . sin (90° - a)
= sin a . sin a + cos a . cos a
= sin² a + cos² a
= 1
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2][
tan² a + 1
= (sin² a + cos² a)/cos² a
= sec² a
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