Công thức các góc trong tam giác

   Công thức các góc trong tam giác:

    Với $\alpha, \beta, \gamma$ là 3 góc trong 1 tam giác: 

• $sin\alpha + sin\beta + sin\gamma = 4cos\dfrac{\alpha}{2}cos\dfrac{\beta}{2}cos\dfrac{\gamma}{2}$
• $cos\alpha + cos\beta + cos\gamma= 4sin\dfrac{\alpha}{2}sin\dfrac{\beta}{2}sin\dfrac{\gamma}{2}+1$
• $sin\alpha+sin\beta-sin\gamma = 4sin\dfrac{\alpha}{2}sin\dfrac{\beta}{2}cos\dfrac{\gamma}{2}$
• $cos\alpha+cos\beta - cos\gamma= 4cos\dfrac{\alpha}{2}cos\dfrac{\beta}{2}sin\dfrac{\gamma}{2}-1$
• $sin^2\alpha + sin^2\beta + sin^2\gamma = 2cos\alpha cos\beta cos\gamma+2$
• $sin^2\alpha + sin^2\beta- sin^2\gamma= 2sin\alpha sin\beta cos\gamma$
• $sin2\alpha+sin2\beta + sin2\gamma= 4sin\alpha sin\beta sin\gamma$
• $sin2\alpha + sin2\beta -sin2\gamma = 4cos\alpha cos\beta sin\gamma$
• $tan\alpha + tan\beta +tan\gamma = tan\alpha tan\beta tan\gamma$
• $cot\dfrac{\alpha}{2} + cot\dfrac{\beta}{2}+ cot\dfrac{\gamma}{2}= cot\dfrac{\alpha}{2} cot\dfrac{\beta}{2} cot\dfrac{\gamma}{2}$
• $cot\alpha cot\beta + cot\alpha cot\gamma + cot\beta cot \gamma = 1$