三角函数解答((sin35)^2-0.5)-0.5))/(cos10*cos80)=?A+B+C=180 tana+tanB+根号3=根号3*tanA*tanb.c=?第一个式子是(sin35^2-0.5)/(cos10*cos80)=?
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![三角函数解答((sin35)^2-0.5)-0.5))/(cos10*cos80)=?A+B+C=180 tana+tanB+根号3=根号3*tanA*tanb.c=?第一个式子是(sin35^2-0.5)/(cos10*cos80)=?](/uploads/image/z/8649962-26-2.jpg?t=%E4%B8%89%E8%A7%92%E5%87%BD%E6%95%B0%E8%A7%A3%E7%AD%94%28%28sin35%29%5E2-0.5%29-0.5%29%29%2F%28cos10%2Acos80%29%3D%3FA%2BB%2BC%3D180+tana%2BtanB%2B%E6%A0%B9%E5%8F%B73%3D%E6%A0%B9%E5%8F%B73%2AtanA%2Atanb.c%3D%3F%E7%AC%AC%E4%B8%80%E4%B8%AA%E5%BC%8F%E5%AD%90%E6%98%AF%28sin35%5E2-0.5%29%2F%28cos10%2Acos80%29%3D%3F)
三角函数解答((sin35)^2-0.5)-0.5))/(cos10*cos80)=?A+B+C=180 tana+tanB+根号3=根号3*tanA*tanb.c=?第一个式子是(sin35^2-0.5)/(cos10*cos80)=?
三角函数解答
((sin35)^2-0.5)-0.5))/(cos10*cos80)=?
A+B+C=180 tana+tanB+根号3=根号3*tanA*tanb.c=?
第一个式子是(sin35^2-0.5)/(cos10*cos80)=?
三角函数解答((sin35)^2-0.5)-0.5))/(cos10*cos80)=?A+B+C=180 tana+tanB+根号3=根号3*tanA*tanb.c=?第一个式子是(sin35^2-0.5)/(cos10*cos80)=?
(sin35^2-0.5)/(cos10*cos80)
=[(1-cos70°)/2-0.5]/[1/2 (cos90°+cos(-70°))]
=(-1/2 cos70°)/(1/2cos70°)
=-1
A+B+C=180 tana+tanB+根号3=根号3*tanA*tanb
tanC=-tan(A+B)=-(tanA+tanB)/(1-tanAtanB)
=-(根号3*tanA*tanB-根号3)/(1-tanAtanB)
=根号3
所以
C=60°.
(sin^2(35°)-1/2)/cos10°cos80°
=cos70°/2cos10°cos80°
=cos70°/(cos90°+cos70°)
=1
tanA+tanB+√3tanAtanB=√3,
(tanA+tanB)=√3(1-tanAtanB),
tan(A+B)=(tanA+tanB)/(1-tanAtanB)=√3,
A+B=60°,
C=180°-(A+B)=120°
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