For questions 1 – 5, decide whether the equation is a trigonometric identity. Explain your reasoning.

Always happy to save a life.......or even bail somebody out on Trig homework..LOL!!!

1. cos² x(1 + tan² x) = 1
2. sec x tan x(1 – sin² x) = sin x
3. csc x(2sin x - √2) = 0
4. cos²(2x) – sin²(2x) = 0
5. sin² θ csc² θ = sin² θ + cos² θ

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1.  cos^2x (1 +tan^2x)  = 1  ???

     cos^2x (sec^2x)  = 1

     cos^2x(1/cos^2x) = 1   identity

2.  secx tanx (cos^2x)  = sinx ??? 

(1/cosx)(sinx/cosx)(cos^2x)  = sinx

[(sinx)/(cos^2x)]cos^2x  = sinx

sinx = sinx     identity

3 and 4 aren't indentites...these are equations....some values of x may make them true, but not all values 

5. sin^2x csc^2x  = sin^2x + cos^2x  ???

sin^2x(1/sin^2x)  = 1

1 = 1   identity

Thank you so much Chris! You saved my life!

lol yea yea. i confess. haha

Hi Brittany :)

Melody! how r u!? :D

I'm great thanks, it is good to see you one the forum. :)

yes! /i was busy traveling (Pittsburgh,PA) and got extremely busy. but, yes, i am very happy to be back! :)