Zad.1 Uzasadnij tożsamość :    [latex]frac{1-2sin^{2}alpha}{sinalpha*cosalpha} = tgalpha - ctgalpha[/latex]  Zadanie. 2 Oblicz a -b gdy  [latex]a=sin^{4}alpha - cos^{4}alpha, b= 1 - 4sin^{2}alpha cos^{2}alpha [/latex] dla a=60 stopni.  

1. tga-ctga=sina/cosa-cosa/sina=(sin2a-cos2a)/sina*cosa=(sin2a-(1-sin2a))/sina*cosa= =(sin2a-1+sin2a)/sina*cosa=(2sin2a-1)/sina*cosa=-(1-2sin2a)/sina*cosa= to by znaczylo ze zgubiles gdzies minusa dla tej tozsamosci(albo ja:) )  2. sin4x-cos4x+4sin2xcos2x-1= =(sin2x+cos2x)(sin2x-cos2x)+4sin2xcos2x-1= =sin2x+4sin2xcos2x-cos2x-sin2x-cos2x= =4sin2xcos2x-2cos2x= =2(2sin2xcos2x-cos2x)= =2cos2x(2sin2x-1)= =2cos2x(2(1-cos2x)-1)= =2cos2x(2-2cos2x-1)=  =2cos2x(1-2cos2x)= =2cos2(60)(1-2cos2(60))= =2(1/2)^2(1-2(1/2)^2)= =1/2(1-1/2)= =1/4   pozdr ar