100 баллов!!!!!!!!!!

task/29726620 см ПРИЛОЖЕНИЕ

9.084   c² =a²+b² -2abcosC =8²+10² -2*8*10*43/160 =64+100 -43 = 121 ⇒c =11.

9.085.  b/2=c*sin(β/2)⇔b=2c√[(1-cosβ)/2) ] ⇔b=2*19√[(1 -7/8)/2] =2*19*1/4 =9,5.

9.085   10 /sinα = 5/sinβ ⇔ sinα= 2sinβ ⇔sin(90+β)= 2sinβ ⇔ cosβ =2sinβ ⇒

tgβ = 1/2  .