Решите неравенство cos5xcos4x+sin5xsin4x<корень из 3/2

Question

Решите неравенство cos5xcos4x+sin5xsin4x<корень из 3/2

Answer 1

Cos5x cos4x + sin5x sin4x <√3/2<br>cos(5x-4x) <√3/2<br>cosx <√3/2<br>π/6 + 2πn < x < (2π -π/6) +2πn, n∈Z
π/6+2πn < x < 11π/6 + 2πn, n∈Z

Answer 2

cos5x*cos4x + sin5x*sin4x< (√3) /2
cos(5x-4x)< (√3) /2
cosx< (√3) /2
cosx < (√3) /2
π|6 +2πn
π/6+2πn