Răspuns:
Explicație pas cu pas:
BC² = AB² + AC² = (18√2)² + (6√30)² = (24√3)²
⇒ BC = 24√3
b) sinB = AC/BC = 6√30/24√3 = √10/4
cosB = AB/BC = 18√2/24√3 = 3√2/4√3 = √6/4
tgB = sinB/cosB = (√10/4) : (√6/4) = (√10/4) · (4/√6) = √5/√3 = √15/3
ctgB = 1/tgB = √3/√5 = √15/5
d) tg²C - tgB · ctgB = (AB/BC)² - (√15/3) · (√15/5) =
= (18√2/24√3)² - 1 = (3√2/4√3)² - 1 = 3/8 - 1 =
= -5/8
