Question

11-16sin*x+16cosx=0 "*"- обозначает квадрат)))

Answer 1

11-16+16cos^x+16cosx=0

cosx=t

16t^+16t-5=0

t=(-8+-sqrt(64+80))/16=(-8+-12)/16

t=4/16=1/4

cosx=1/4

x=arccos(1/4)+2Пk