We need to prove that :
sinx+
tanx / (1+ sec x ) = sinx
We will start from the left
side.
(sinx + tanx)/ (1+
secx)
We know that tanx = sinx/cosx ans secx =
1/cosx.
Then, we will substitute with
identities.
==> (sinx+ sinx/cosx) / (1+
1/cosx)
==> [(sinx*cosx + sinx)/cosx] / [ ( cosx +
1)/cosx]
Reduce
cosx.
==> (sinxcosx + sinx ) / (cosx +
1)
Now we will factor sinx from the
numerator.
==>
sinx*(cosx+1)/(cosx+1)
Now we will reduce
cosx+1
==>
sinx
Then we proved that (
sinx+tanx)/(1+secx) = sinx.
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