C3 question help

Hi. I have included my working out for question 5. I get an answer of
e^-x sec2x(tan2x-1)

However the book says the answer is:
e^-x sec2x(tan2x-1)

I can't figure out where the extra 2 has come from

Any help will be appreciated.
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So,
let u=e^-x and v=sec2x
so dv/dx= 2sec2xtan2x
and du/dx= -e^-x
so dy/dx= -e^(-x)sec2x+ 2e^(-x)sec2xtan2x
so e^(-x)sec2x(2tan2x-1)