prosze o rozwiazanie zadan w załaczniku  - dział trygonometria

[latex]a) frac{sin^2 alpha }{1+cos alpha }= frac{1-cos^2 alpha }{1+cos alpha }= frac{(1+cos alpha )(1-cos alpha )}{1+cos alpha }=1-cos alpha [/latex] [latex]b) frac{2cos^2 alpha -1}{1-2sin^2 alpha }= frac{2(1-sin^2 alpha )-1}{1-2sin^2 alpha}= frac{2-2sin^2 alpha -1}{1-2sin^2 alpha}= frac{1-2sin^2 alpha}{1-2sin^2 alpha}=1 [/latex] [latex]c) frac{1-sin^2 alpha }{1-cos^2 alpha }= frac{cos^2 alpha }{sin^2 alpha }= (frac{cos alpha }{sin alpha })^2 = ctg^2 alpha [/latex] [latex]d) sin^4 alpha -cos^4 alpha +cos^2 alpha =sin^4 alpha +cos^2 alpha (-cos^2 alpha +1)=sin^4 alpha +cos^2 alpha *sin^2 alpha =sin^2 alpha (sin^2 alpha +cos^2 alpha )=sin^2 alpha [/latex]