sin a=4/10 berapa nilai cos a? dan tan a?

Kelas 10 Matematika
Bab Trigonometri Dasar

Sin a = 4/10 → y/r

x = √(r² - y²)
x = √(10² - 4²)
x = √(100 - 16)
x = √84
x = √4 . √21
x = 2√21

cos a = x/r
cos a = (2√21) / 10
cos a = (1/5) √21

tan a = y/x
tan a = 4/(2√21)
tan a = 2/√21 . (√21)/(√21)
tan a = (2√21)/√21²
tan a = (2/21) √21