Assalamualiakum teman-teman ……
Saya membuat blog ini untuk memudahkan teman-teman mengetahui apa itu trigonometri. Sebelum mengetahui apa itu trigonometri. Marilah kita ketahui sudut-sudut istimewa trigonometri.
keterangan :
td = tak hingga
Penghitungan sudut sesuai dengan kuadrannya :
Kuadran I
- cos (90 – x)˚ = sin x
- tan (90 – x)˚ = cot x
- cot (90 – x)˚ = tan x
Kuadran II
- sin (90 + x)˚ = cos x
- cos (90 + x)˚ = –sin x
- tan (90 + x)˚ = –cot x
- cot (90 + x)˚ = –tan x
- sin (180 – x)˚ = sin x
- cos (180 – x)˚ = –cos x
- tan (180 – x)˚ = –tan x
- can (180 – x)˚ = –can x
Kuadran III
- sin (180 + x)˚ = –sin x
- cos (180 + x)˚ = –cos x
- tan (180 + x)˚ = tan x
- cot (180 + x)˚ = cot x
- sin (270 – x)˚ = –cos x
- cos (270 – x)˚ = –sin x
- tan (270 – x)˚ = cot x
- cot (270 – x)˚ = tan x
Kuadran IV
- sin (270 + x)˚ = –cos x
- cos (270 + x)˚ = sin x
- tan (270 + x)˚ = –cot x
- cot (270 + x)˚ = –tan x
- sin (360 – x)˚ = –sin x
- cos (360 – x)˚ = cos x
- tan (360 – x)˚ = –tan x
- cot (360 – x)˚ = –cot x
Beberapa aturan Trigonometri :
- tan x = sin x / cos x
- cot x = cos x / sin x
- cosec x = 1 / sin x
- sec x = 1 / cos x
- cot = 1 / tan x
Identitas Trigonometri :
- sin² x + cos² x = 1
- tan² x + 1 = sec² x
- cot² + 1 = cosec² x
Persamaan sudut Trigonometri :
- sin 2x = 2 sin x cos x
- cos 2x = cos² x – sin² x = 2 cos² x – 1 = 1 – 2 sin² x
- tan 2x = (2 tan x) / (1 – tan² x)
Aturan perkalian Trigonometri :
- sin (A + B) = sin A cos B + cos A sin B
- sin (A – B) = sin A cos B – cos A sin B
- cos (A + B) = cos A cos B – sin A sin B
- cos (A – B) = cos A cos B + sin A. sin b
- tan (A + B) = (tan A + tan B) / (1 – tan A tan B)
- tan (A – B) = (tan A – tan B) / (1 + tan A tan B)
Perkalian Sin dan Cos :
- sin A cos B = 1/2 (sin (A + B) + sin (A – B))
- cos A sin B = 1/2 (sin (A + B) – sin (A – B))
- cos A cos B = 1/2 (sin (A + B) + cos (A – B))
- sin A sin B = 1/2 (sin (A – B) – cos (A + B))
Penjumlahan Trigonometri :
- sin A + sin B = 2 sin ½(A + B) cos ½(A – B)
- sin A – sin B = 2 cos ½(A + B) sin ½(A – B)
- cos A + cos B = 2 cos ½(A + B) cos ½(A – B)
- cos A – cos B = –2 sin ½(A + B) sin ½(A – B)
- tan A + tan B = 2 sin (A + B) / {cos (A + B) + cos (A – B)}
- tan A – tan B = 2 sin (A + B) / {cos (A + B) + cos (A – B)}
Sekian mengenai Trigonometri. Semoga bermanfaat ya teman-teman.
Wahh sangat membantu sekali
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Alhamdulillah, tunggu pos yang selanjutnya ya
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