How do you prove (sinx + tanx) / cosx + 1 = tanx?

1 Answer
Alan P.
Jan 25, 2016

The given equation is not true and therefore can not be proven.

Explanation:

Consider for example the case when x=0

color(white)("XXX")cos(0) = 1
color(white)("XXX")sin(0) = 0

So when x=0
color(white)("XXX")(sin x + tan x)/(cos x) + 1 = tan x +1
which obviously can not be equal to
color(white)("XXX")tan x

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