Im so sorry but I don't know this answer
- cos ( 1/2 x + 1/5 π ) = 0 ( and because if cos α = 0, α= π/2 + k π, k ∈ Z )
1/2 x + π/5 = π/2 + k π, k ∈ Z
1/2 x = π/2 - π/5 + k π / * 2
x = π - 2π/5 + 2 k π
x = 3/5 π + 2 k π = 0.6 π + 2 k π
Answer:
If k = 0: x 1 = 0.6 π = 3π/5
k = 1 : x 2 = 2.6 π = 13π/5
First you will have too find the least common multiple which is 20 and what you multiplied to get 20 multiply it which will make 3/5 to 12/20 and 1/4 too 4/20 and then subtract the two which is 8/20 or 8 oranges. if you need more information talk too me