Question

tg^2a+ctg^2a, если tga + ctga =2

Answer 1

$tan a + cot a =2\\(tan a + cot a)^2 =2^2\\tan^2a+2cdottan acdotcot a+cot^2a=4\\tan^2a+2cdot 1+cot^2a=4\\tan^2a+cot^2a=2$