Cos (п/10) + sin (п/10) преобразовать в сумму

Cosπ/10+sinπ/10=√2sin (π/4+π/10) =

√2sin (5π+2π) / 20=√2sin7π/20

2) cos (π/2-4π/10) + sinπ/10=

sin4π/10+sinπ/10=

2sin ((5π/10) : 2) * cos (3π/10) : 2

=2sin (π/4) * cos (3π/20) =

2 * (√2/2) * cos (3π/20) =

√2cos (3π/20)