回答:
请看下面
说明:
#LHS = 1-sin4x + COT((3PI)/ 4-2x)* cos4x#
#= 1-sin4x +(COT((3PI)/ 4)* cot2x + 1)/(cot2x-COT((3PI)/ 4))* cos4x#
#= 1-sin4x +((COT(π-π/ 4)* cot2x + 1)/(cot2x-COT(π-π/ 4)))* cos4x#
#= 1-sin4x +( - COT(PI / 4)* cot2x + 1)/(cot2x - ( - 婴儿床(PI / 4)))* cos4x#
#= 1-sin4x +(1-cot2x)/(1个+ cot2x)* cos4x#
#= 1-sin4x +(1-(cos2x)/(sin2x))/(1+(cos2x)/(sin2x))* cos4x#
#= 1-sin4x +(sin2x-cos2x)/(sin2x + cos2x)* cos4x#
#= 1 +(2(sin2x * cos4x-cos4x * cos2x-sin4x * sin2x-sin4x * cos2x))/(2(sin2x + cos2x))#
#= 1 +(SIN(4X + 2×)-sin(4X-2×)-cos(4X + 2×)-cos(4X-2×)-cos(4X-2×)+ COS(4X + 2×)-sin(4倍+ 2×)-sin(4X-2×))/(2(sin2x + cos2x)#
#= 1 +(sin6x-sin2x-cos6x-cos2x-cos2x + cos6x-sin6x-SIN(2×))/(2(sin2x + cos2x)#
#= 1-取消((2-(sin2x + cos2x))/(2(sin2x + cos2x)))#
#= 1-1 = 0 = RHS#