Question

tg(a-7p/2) если tga= 1,25

Answer 1

$tg(\alpha-\frac{7\pi }{2} )=-tg(\frac{7\pi }{2}-\alpha)=-tg(3\pi+\frac{\pi }{2}-\alpha)=-tg(\frac{\pi }{2}-\alpha)=-Ctg\alpha=-\frac{1}{tg\alpha }=-\frac{1}{1,25}=-\frac{100}{125} =-0,8$