Buktikan bahwa cos kuadrad A + Sinus kuadrad A=1 Please bantu dong gengs secepatnya..

Bab Trigonometri
Matematika SMA Kelas X

cos² A + sin² A = 1

pada tripel pitagoras,
cos A = x/r
sin A = y/r
di mana, x² + y² = r²

cos² A + sin² A = 1
(x/r)² + (y/r)² = 1
x²/r² + y²/r² = 1
(x² + y²)/r² = 1
r² / r² = 1
1 = 1

terbukti 

sin^a + cos^a = 1
misal a= 30°
sin^30°+cos^30° = (sin 30°)^ + (cos 30°)^
= (1/2)^ + (1/2√3)^ = 1/4+3/4 = 1

semoga benar