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a) ![\frac{(1-cosa)(1+cosa)}{sina+sin( \pi -a)}=\frac{1-cos^{2}a}{sina+sina}=\frac{sin^{2}a}{2sina}=0.5*sina \frac{(1-cosa)(1+cosa)}{sina+sin( \pi -a)}=\frac{1-cos^{2}a}{sina+sina}=\frac{sin^{2}a}{2sina}=0.5*sina](https://tex.z-dn.net/?f=%5Cfrac%7B%281-cosa%29%281%2Bcosa%29%7D%7Bsina%2Bsin%28+%5Cpi+-a%29%7D%3D%5Cfrac%7B1-cos%5E%7B2%7Da%7D%7Bsina%2Bsina%7D%3D%5Cfrac%7Bsin%5E%7B2%7Da%7D%7B2sina%7D%3D0.5%2Asina)
б)![(5-2 \sqrt{6})^{2}-(3\sqrt{2}-2\sqrt{3})(4\sqrt{2}+8\sqrt{3})=25-20\sqrt{6}+4*6-(12*2+24\sqrt{6}-8\sqrt{6}-16*3)=25-20\sqrt{6}+24-24-24\sqrt{6}+8\sqrt{6}+48=-36\sqrt{6}+73 (5-2 \sqrt{6})^{2}-(3\sqrt{2}-2\sqrt{3})(4\sqrt{2}+8\sqrt{3})=25-20\sqrt{6}+4*6-(12*2+24\sqrt{6}-8\sqrt{6}-16*3)=25-20\sqrt{6}+24-24-24\sqrt{6}+8\sqrt{6}+48=-36\sqrt{6}+73](https://tex.z-dn.net/?f=%285-2+%5Csqrt%7B6%7D%29%5E%7B2%7D-%283%5Csqrt%7B2%7D-2%5Csqrt%7B3%7D%29%284%5Csqrt%7B2%7D%2B8%5Csqrt%7B3%7D%29%3D25-20%5Csqrt%7B6%7D%2B4%2A6-%2812%2A2%2B24%5Csqrt%7B6%7D-8%5Csqrt%7B6%7D-16%2A3%29%3D25-20%5Csqrt%7B6%7D%2B24-24-24%5Csqrt%7B6%7D%2B8%5Csqrt%7B6%7D%2B48%3D-36%5Csqrt%7B6%7D%2B73)
г) Если правильно разобрала почерк.
![\left \{ {{a_{5}+a_{10}=-9} \atop {a_{4}+a_{6}=-11}} \right. \left \{ {{a_{5}+a_{10}=-9} \atop {a_{4}+a_{6}=-11}} \right.](https://tex.z-dn.net/?f=+%5Cleft+%5C%7B+%7B%7Ba_%7B5%7D%2Ba_%7B10%7D%3D-9%7D+%5Catop+%7Ba_%7B4%7D%2Ba_%7B6%7D%3D-11%7D%7D+%5Cright.)
![\left \{ {{a_{1}+4d+a_{1}+9d=-9} \atop {a_{1}+3d+a_{1}+5d=-11}} \right. \left \{ {{a_{1}+4d+a_{1}+9d=-9} \atop {a_{1}+3d+a_{1}+5d=-11}} \right.](https://tex.z-dn.net/?f=+%5Cleft+%5C%7B+%7B%7Ba_%7B1%7D%2B4d%2Ba_%7B1%7D%2B9d%3D-9%7D+%5Catop+%7Ba_%7B1%7D%2B3d%2Ba_%7B1%7D%2B5d%3D-11%7D%7D+%5Cright.)
![\left \{ {{2a_{1}+13d=-9} \atop {2a_{1}+8d=-11}} \right. \left \{ {{2a_{1}+13d=-9} \atop {2a_{1}+8d=-11}} \right.](https://tex.z-dn.net/?f=+%5Cleft+%5C%7B+%7B%7B2a_%7B1%7D%2B13d%3D-9%7D+%5Catop+%7B2a_%7B1%7D%2B8d%3D-11%7D%7D+%5Cright.)
![5d=2 5d=2](https://tex.z-dn.net/?f=5d%3D2)
![d=0.4 d=0.4](https://tex.z-dn.net/?f=d%3D0.4)
![2a_{1}+13d=-9 2a_{1}+13d=-9](https://tex.z-dn.net/?f=2a_%7B1%7D%2B13d%3D-9)
![2a_{1}=-9-13d=-9-13*0.4=-14.2 2a_{1}=-9-13d=-9-13*0.4=-14.2](https://tex.z-dn.net/?f=2a_%7B1%7D%3D-9-13d%3D-9-13%2A0.4%3D-14.2)
![S_{10}=\frac{2a_{1}+9d}{2}*10=5*(2a_{1}+9d)=5*(-14.2+9*0.4)=-53 S_{10}=\frac{2a_{1}+9d}{2}*10=5*(2a_{1}+9d)=5*(-14.2+9*0.4)=-53](https://tex.z-dn.net/?f=S_%7B10%7D%3D%5Cfrac%7B2a_%7B1%7D%2B9d%7D%7B2%7D%2A10%3D5%2A%282a_%7B1%7D%2B9d%29%3D5%2A%28-14.2%2B9%2A0.4%29%3D-53)
б)
г) Если правильно разобрала почерк.
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