Trigo formula

Trigo formula

t = tan A/2
1. tan A = 2t / (1-t^2)
2. cos A = (1 - t^2) / (1 + t^2)
3. sin A = 2t / (1 + t^2)
Product formula
1. sin A + sin B = 2 sin [(A+B) /2] cos [(A-B) /2]
2. sin A - sin B = 2 cos [(A+B) /2] sin [(A-B) /2]
3. cos A + cos B = 2 cos [(A+B) /2] cos [(A-B) /2]
4. cos A - cosB = - 2 sin [(A+B) /2] sin [(A-B) /2]
Equalities
1. sin^2 x+ cos^2 =1
2. 1 + tan^2 x = sec^2 x
3. 1+cot^2 x = csc^ x
和角公式
1. sin (A+B) = sin A cos B + cos A sin B
2. cos (A+B) = cos A cos B - sin A sin B
3. tan (A+B) = (tan A+ tan B) / (1 - tanA tanB)
4. sin (A-B) = sin A cos B - cos A sin B
5. cos (A-B) = cos A cos B + sin A sin B
6. tan (A-B) = (tan A - tan B) / (1 + tanA tanB)

Resource summary

	Created by Low Yee Shen about 9 years ago