展开 4(1+cos(12pit)=8cos^2(6pit))

解答

展开

4 (1 + cos (12 π t) = 8 cos^{2} (6 π t))

4 + 4 cos (12 π t) = 8 cos^{2} (6 π t)

求解步骤

4 (1 + cos (12 π t) = 8 cos^{2} (6 π t))

= 4 (1 + 8 = cos (12 π t) cos^{2} (6 π t))

使用分配律:

a (b + c) = ab + a c

a = 4, b = 1, c = cos (12 π t) = 8 cos^{2} (6 π t)

4 \cdot 1 + 4 cos (12 π t) = 8 cos^{2} (6 π t)

乘开

4 \cdot 1 + 4 cos (12 π t) : 4 + 4 cos (12 π t)

4 + 4 cos (12 π t) = 8 cos^{2} (6 π t)

e x p an d 5 - 8 + (- 4) - (- 3)

e x p an d (e + 1) (e - 1)

e x p an d 3 (5 x) - 2

e x p an d \frac{( x - 4 ) y}{( x - 4 ) ^{2} + y ^{2}}

e x p an d (1 + 3 i) (4 + 3 i)