计算cos(1/2arctan(-3/4))

计算cos(1/2arctan(-3/4)) cos[1/2arctan(-3/4)].cos[1/2arctan(-3/4)]= cos[arctan(1/2) - arctan(-2)]=? 求 cos[2arctan(3/4)]的值 求值1.cos[arcsin(-4/5)-arctan(-3/4)]2.sin[1/2arcsin(-12/13)] cos[2arctan(-1/2)]=? 求值：sin[1/2arctan(-4/3)] cos(arctan(-2)-arcsin3/5) arctan(-2)+arctan(-3)=? 求值arctan（ cot2）,tan(1/2arccos4/5),cos[arcsin(-3/5)],arcsin(cos1/3) 高一数学：tan[arcsin1+arctan(-√3/3)]+cos[arccos(-1/2)+arctan0] cos(2arctan√2+π/3)的值为 求值cos(2arctan根号6+pai/3) 用复变函数证明arctan (1/2) + arctan (1/3) =π/4 求arctan（1／5）＋arctan（2／3）答案为 派／4 arctan(1/3)+arctan(1/2)的值为? 级数求和：arctan(1/2)+arctan(1/2^2)+arctan(1/2^3)+...+arctan(1/2^n)+... 求证：arctan 1/2+arctan 1/5+arctan 1/8=π/4