Question

№29.2 Помогите срочн!!!
1) sin7*cos23+sin23*cos7+1
2)4sin25*sin65 /cos40
3)tg22+tg23 /1-tg22*tg23

Answer 1

Решение на фото ........

Answer 2

$\displaystyle\bf\\1)\\\\Sin7^\circ\cdot Cos23^\circ+Sin23^\circ \cdot Cos7^\circ+1=Sin(7^\circ+23^\circ)+1=\\\\=Sin30^\circ+1=0,5+1=1,5\\\\2)\\\\\frac{4Sin25^\circ\cdot Sin65^\citrc}{Cos40^\circ} =\frac{4Sin25^\circ\cdot Sin(90^\circ-25^\circ)}{Cos40^\circ} =\\\\\\=\frac{2\cdot(2Sin25^\circ\cdot Cos25^\circ)}{Cos(90^\circ-50^\circ)} =\frac{2Sin50^\circ}{Sin50^\circ} =2\\\\\\3)\\\\\frac{tg22^\circ+tg23^\circ}{1-tg22^\circ\cdot tg23^\circ} =tg(22^\circ+23^\circ)=tg45^\circ=1$

$\displaystyle\bf\\4)\\\\Sin64^\circ Cos26^\circ+Cos64^\circ Sin26^\circ-Sin30^\circ=\\\\=Sin(64^\circ+26^\circ)-0,5=Sin90^\circ-0,5= 1-0,5=0,5$