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johnnyalln
Simplify the expression: \[(\tan \Theta+1)(\tan \Theta-1)\]
See how each set of brackets contains the same thing except with a sign change? These are CONJUGATES. When you multiply conjugates you get the difference of squares. Example:\[\large (x-y)(x+y)=x^2-y^2\]
what about \[\tan^{2} \Theta-1\]
Yup looks good! c: And since we don't have an identity for tan^2 - 1, it looks like that's as far as we can simplify it.