Question

упростите 

 

1-sin^2+ctg^2*sin^2

 

 

Answer 1

$1-sin^{2}x+ctg^{2}x*sin^{2}x=cos^{2}x+frac{cos^{2}x}{sin^{2}x}*sin^{2}x=$

 

$=cos^{2}x+cos^{2}x=2cos^{2}x$