i need help proving the indentity

**valvan** · November 5th 2009, 03:31 PM

(1/1-sinx)-(1/1+sinx)=2sectan
i got stumped on this one

**alexmahone** · November 5th 2009, 03:42 PM

Originally Posted by valvan

(1/1-sinx)-(1/1+sinx)=2sectan
i got stumped on this one

$\frac{1}{1-sinx}-\frac{1}{1+sinx}$

= $\frac{2sinx}{1-sin^2x}$

= $\frac{2sinx}{cos^2x}$

= $2\frac{1}{cosx}\frac{sinx}{cosx}$

= $2secxtanx$

**valvan** · November 5th 2009, 03:52 PM

can you explain further how you got to
=

**mathaddict** · November 5th 2009, 05:59 PM

Originally Posted by valvan

can you explain further how you got to
=

HI

$\frac{1}{1-sinx}-\frac{1}{1+sinx}$

Just combine the fractions .

$\frac{1+\sin x}{(1-\sin x)(1+\sin x)}-\frac{1-\sin x}{(1+\sin x)(1-\sin x)}$

**pacman** · November 5th 2009, 08:49 PM

= Numerator/Denomenator

Numerator = (1 + sin x) - (1 - sin x) = 1 + sin x - 1 + sin x = ?

Thread: i need help proving the indentity