Question

Помогите с алгеброй дам много балов​

Answer 1

Sin105⁰ * Cos285⁰ = Sin(90⁰ + 15⁰) * Cos(270⁰ + 15⁰) = Cos15⁰ * Sin15⁰ =

= 1/2 * (2 * Sin15⁰Cos15⁰ ) = 1/2 Sin30⁰ = 1/2 * 1/2 = 1/4 = 0,25