Докажите тождество:sin^4B+sin^2B cos^2B+cos^2B=1

Question

Докажите тождество:
sin^4B+sin^2B cos^2B+cos^2B=1

Answer 1

Sin^4b+sin^2bcos^2b+cos^2b=sin^2b(sin^2b+cos^2b)+cos^2b=sin^2b+cos^2b=1