# 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:

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