Question

Pre Cal
verify identity
sec(a+B)=secasecB/1-tanatanB

Answer 1

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Answer 2

\[\sec(a+B)= (\sec a secB)/(1-tanatanB)\]\[=(1/cosa)( 1/cosB)/1-(sina/cosa)(sinB/cosB)\]
Multiply top and bottom by \[(cosa)(cosB)\]

That will get you 1/(cosa)(cosB)-(sina)(sinB)

which is 1/cos(a+B)

which is sec(a+B)

Answer 3

and sina sinb is 1-tanatanb