Posted by **Matt** on Monday, April 27, 2009 at 9:11pm.

I do not understand these problems. :S

I'd really appreciate the help.

Use trigonometric identities to transform the left side of the equation into the right side.

cot O sin O = cos O

sin^2 O - cos^2O = 2sin^2 O -1

(tan O + cot O)/tan O = csc^2 O

- trig -
**Reiny**, Monday, April 27, 2009 at 9:31pm
for most of these you have to know your basic trig relationships

tanx = sinx/cosx ; cotx = cosx/sinx

cscx = 1/sinx ; secx = 1/cosx

sin^{2}x + cos^{2}x = 1

and its re-arrangements.

so for the first :

LS = cotOsinO

= (cosO/sinO)(sinO)

= sinO

= RS

Most are this easy.

last one : (I will use x as my angle)

LS

= (sinx/cosx + cosx/ sinx)/(sinx/cosx)

= (sin^{2}x + cos^{2}x)/(sinxcosx) x (cosx/sinx)

= 1/(sinxcosx)(cosx/sinx)

= 1/sin^{2}x

= csc^{2}x

= RS

try the second one, it is even easier.

- trig -
**Steve Madden**, Tuesday, April 20, 2010 at 4:04pm
solve for x to the nearest thousandth: 2tan square x-5tan x-1

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