A = tg 15 . tg55 . cotg15 . cotg55
B = tg20 . tg50 . tg70 . tg40
C= sin ²23 + sin ²43 + cos ²23+ cos ²43
A = tg 15 . tg55 . cotg15 . cotg55 B = tg20 . tg50 . tg70 . tg40 C= sin ²23 + sin ²43 + cos ²23+ cos ²43
By Sadie
By Sadie
A = tg 15 . tg55 . cotg15 . cotg55
B = tg20 . tg50 . tg70 . tg40
C= sin ²23 + sin ²43 + cos ²23+ cos ²43
$A=\tan 15^o.\cot 15^o.\tan 55^o.\cot 55^o$
$=1.1=1$
$B=\tan 20^o.\tan 70^o.\tan 50^o.\tan 40^o$
$=\tan 20^o.\cot 20^o.\tan 50^o.\cot 50^o$
$=1.1=1$
$C=\sin^223^o+\sin^243^o+\cos^223^o+\cos^243^o$
$=\sin^223^o+\cos^223^o+\sin^243^o+\cos^243^o$
$=1+1=2$