Question

спростить виаз sin^2a(1+ctg^2a)​

Answer 1

sin²a · ( 1 + ctg²a ) = *** ctga = cosa/sina ⇒ ctg²a = cos²a/sin²a ***

= sin²a · ( 1 + cos²a/sin²a ) = *** 1 + cos²a/sin²a = ( sin²a + cos²a )/sin²a ***

= sin²a · ( sin²a + cos²a )/sin²a  = *** sin²a + cos²a = 1 ***

sin²a · 1/sin²a = *** сокращаем sin²a ***

= 1 - ответ.