Объяснение:
4. sin(π-x)+cos(π/2-x)*sin(π+x)=sinx+sinx*(-sinx)=sinx-sin^2x=sinx(1-sinx)
5.(cos^2x-1)/(sin^2x-1)-sin^2x-cos^2x=(cos^x-1)/(1-cos^2x-1)-(sin^2x+cos^2x)=(cos^2x-1)/(-cos^2x)-1=-1+1/(cos^2x)-1=-2+1+tg^2x=tg^2x+1=1/cos^2x
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Verified answer
Объяснение:
4. sin(π-x)+cos(π/2-x)*sin(π+x)=sinx+sinx*(-sinx)=sinx-sin^2x=sinx(1-sinx)
5.(cos^2x-1)/(sin^2x-1)-sin^2x-cos^2x=(cos^x-1)/(1-cos^2x-1)-(sin^2x+cos^2x)=(cos^2x-1)/(-cos^2x)-1=-1+1/(cos^2x)-1=-2+1+tg^2x=tg^2x+1=1/cos^2x