1 + tan kuadrat 60 derajat = sec kuadrat 60 derajat

1 + tan²60° = sec²60°
1 + (akar3)² = (1/(1/2))²
1 + 3 = 2²
4 = 4

Bab Trigonometri
Matematika SMA Kelas X

cara pertama, identitas
1 + tan² a = sec² a

cara kedua
1 + tan² 60
= 1 + (√3)²
= 1 + 3
= 4

sec² 60° = (1/( cos 60°))²
sec² 60° = (1/ (1/2))²
sec² 60° = 2²
sec² 60° = 4