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问题: kongjiang15

设方程x+sinx=π/2,的根是x1,方程x+arcsinx=π/2的根是x2,则x1+x2的值是
A.π/2
B.π/4
C.π/3
D.π/8
请写出详细的过程和思路,谢谢

解答:

设方程x+sinx=π/2的根是x1,方程x+arcsinx=π/2的根是x2,则x1+x2的值是

x1+sinx1=π/2...........(1)
x2+arcsinx2=π/2........(2)
(1)中:π/2-x1=sinx1=cos(π/2-x1)....................(3)
(2)中:arcsinx2=π/2-x2
    --->sin(arcsinx2)=sin(π/2-x2)--->x2=cosx2...(4)
比较(3)(4)--->x2=π/2-x1--->x1+x2=π/2.......选A