Diketahui a= [3, 5, 6] dan |b| = √70 jika a . b = 30 dan sudut antara a dan b adalah (tanda) maka nilai tan(tanda) adalah...

(tanda) = x

cos x = a . b/|a| . |b|
cos x = 30/akar(3²+5²+6²) . akar 70
cos x = 30/akar70 . akar 70
cos x = 3/7

sisi samping = 3
sisi miring = 7
sisi depan = 2akar10

tan x = 2akar10/3

a = (3, 5, 6) => |a| = √(3^2 + 5^2 + 6^2) = √(9 + 25 + 36) = √70
a.b = |a|.|b| cos @
30 = √70.√70 cos @
70 cos @ = 30
cos @ = 3/7 = sa/mi => de = √(7^2 - 3^2) = √(49 - 9) = √40 = 2√10

tan @ = de/sa = (2√10)/3 = (2/3) √10