Question

find exact value of cos(23pi/6)

Answer 1

did you notice that 23π/6 is π/6 short of 2π ?

so and angle of 23π/6 is coterminal with -π/6
so cos(23π/6) = cos(-π/6) = cos(π/6)

from the 30-60-90 triangle ratios you should know that cos 30° = √3/2 ...... (30° = π/6 radians)

then cos 23π/6 = √3/2

Answer 2

what is the exact value of tan pi o
ver two