Question

1.
вычислите ctg(t-$3pi$) sin(t+$2pi$) tg(t-$pi$) если cos(t+$2pi$)=-12/13, $pi < t <3 pi /2$
решите неравенство cost>1/2 sint$leq$ 1/2

Answer 1

sin(pi/2+t)-cos(pi-t)+tg(pi-t)+ctg(5pi/2-t)= cost-cos(-t)+tg(-t)+tgt=cost+cost-tgt+tgt=cost+cost=2cost