Tan×+cosx÷1+sinx?

1 Answer
May 16, 2018

tanx+cosx/(1+sinx)=secx=1/cosxtanx+cosx1+sinx=secx=1cosx

Explanation:

I'm assuming you meant cosx-:(1+sinx)cosx÷(1+sinx), as cosx-:1cosx÷1 is trivial.

When we have 1+sinx1+sinx in the denominator, we want to amplify the fraction by 1-sinx1sinx to get 1-sin^2x=cos^2x1sin2x=cos2x.

:. E(x)=tanx+cosx/(1+sinx)*color(red)((1-sinx)/(1-sinx))

E(x) = tanx+(cosx(1-sinx))/(1-sin^2x)=tanx+(cosx(1-sinx))/cos^2x

Simplifying the cosx:

E(x)=tanx+(1-sinx)/cosx

We know, by definition, that tanx=sinx/cosx.

:. E(x) = sinx/cosx+(1-sinx)/cosx=(sinx+1-sinx)/cosx=1/cosx

=>color(red)(E(x)=secx)