Question #bc1af
1 Answer
Dec 29, 2017
See the answer below...
Explanation:
#(tanx+1)^2#
#=tan^2x+2 cdot tanx cdot 1 +1^2#
#=(tan^2x+1)+2cdot tanx#
#=sec^2x+2tanx+(sec^2x-sec^2x)# #" "# #color(red)([sec^x=1+tan^2x]#
#=2sec^2x+(2tanx-sec^2x)#
#=2sec^2x+((2sinx)/cosx-1/cos^2x)# According to your problem, this part
#color(red)(((2sinx)/cosx-1/cos^2x)# should be equal to#color(red)(cos^2x# but it is not true.DOUBLECHECK your problem....
