Question

Дано:
tgx=3/4, tg(π/2−y)=2.
Определи:

1. tg(x+y) =


2. tg(x−y)

Answer 1

Ответ:

$tgx=\dfrac{3}{4}=0,75\ \ ,\\\\tg\Big(\dfrac{\pi}{2}-y\Big)=ctgy=2\ \ \to \ \ tgy=\dfrac{1}{ctgy}=\dfrac{1}{2}=0,5\\\\\\1)\ \ tg(x+y)=\dfrac{tgx+tgy}{1-tgx\cdot tgy}=\dfrac{0,75+0,5}{1-0,75\cdot 0,5}=\dfrac{1,25}{0,625}=\dfrac{1250}{625}=2\\\\\\2)\ \ tg(x-y)=\dfrac{tgx+tgy}{1+tgx\cdot tgy}=\dfrac{0,75-0,5}{1+0,75\cdot 0,5}=\dfrac{0,25}{1,375}=\dfrac{250}{1375}=\dfrac{2}{11}$