设f(x)=cos1/x 则f'(2/π)=?
来源：学生学帮网 编辑：学帮网 时间：2024/06/11 11:16:56
设f(x)=cos1/x 则f'(2/π)=?
首先求f'(x)=?
f(x)=cos(1/x)=-sin(1/x)*(-1/x^2)=sin(1/x)*(1/x^2)
f'(2/π)=sin(π/2)*1/(π/2)^2=4/π^2
设f(x)=cos1/x 则f'(2/π)=?
首先求f'(x)=?
f(x)=cos(1/x)=-sin(1/x)*(-1/x^2)=sin(1/x)*(1/x^2)
f'(2/π)=sin(π/2)*1/(π/2)^2=4/π^2