The value of e-π4+∫0π4e-xtan50x dx∫0π4e-x(tan49x+tan51x) dx is: [2023]
(4)
e-π/4+∫0π/4e-xtan50x dx∫0π/4e-x(tan49x+tan51x)dx
First, simplify, ∫0π/4e-xtan50xdx
=[-e-x(tanx)50]0π/4+∫0π/4e-x(50)tan49x·sec2x dx
=-e-π/4+0+50∫0π/4e-x(tanx)49(1+tan2x) dx
=-e-π/4+50∫0π/4e-x[(tanx)51+(tanx)49]dx
Now, -e-π/4+∫0π/4e-x(tanx)50dx∫0π/4e-x(tan49x+tan51x)dx
=50∫0π/4e-x(tan51x+tan49x)dx∫0π/4e-x(tan49x+tan51x)dx=50
∴ e-π/4+∫0π/4e-xtan50x dx∫0π/4e-x(tan49x+tan51x)dx=50