Question

1)-1sin^2a-cos^2a+1
2) ctga-cos^2a•ctga
3) sin^2a/cos^2•ctga
4) ctg^2+cos^2a/sin^2a
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Answer 1

Ответ:

1)-1sin²a-cos²a+1=-sin²a-cos²a+sin²a+cos²a=0

1=sin²a+cos²a

2)ctga-cos²a×ctga°ctga(1-cos²a)=ctga×sin²a=cosa/sina×sin²a=cosa×sina

1-cos²a=sin²a

3)sin²a/cos²a×ctga=sin²a×cosa/cos²a×sina=sin²acosa/cos²a=sin²a/cos²a×cosa/cos²a=tg²a×secx

4)ctg²a+cos²a/sin²a=ctg²a+ctg²a=2ctg²a