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Help Verifying Trig Identities

Help verifying trig identities?

Do not convert everything to sinθ and cosθ for either of these identities.
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1) Verify the identity.

[(secθ - tanθ)² + 1] / (secθ cscθ - tanθ cscθ) = 2 tan θ

Let's start with the left hand side.

Left Hand Side

= [(secθ - tanθ)² + 1] / (secθ cscθ - tanθ cscθ)

= [sec²θ - 2tanθ secθ + tan²θ + 1] / [cscθ(secθ - tanθ)]

= [sec²θ + (tan²θ + 1) - 2tanθ secθ] / [cscθ(secθ - tanθ)]

= [2sec²θ - 2tanθ secθ] / [cscθ(secθ - tanθ)]

= [2secθ(secθ - tanθ)] / [cscθ(secθ - tanθ)]

= 2secθ / cscθ = 2sinθ / cosθ = 2 tanθ = Right Hand Side
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2) Verify the identity.

1 / (secθ - tanθ) = secθ + tanθ

Let's work with the left hand side.

Left Hand Side = 1 / (secθ - tanθ)

= (secθ + tanθ) / [(secθ - tanθ)(secθ + tanθ)]

= (secθ + tanθ) / (sec²θ - tan²θ)

= (secθ + tanθ) / 1 = secθ + tanθ = Right Hand Side

Verifying trig identities?

sin x ( 1 + cot^2 x) ==> use the Pyth ID that csc^2 x = 1 + cot^2 x

sin x ( csc^2 x )
sin x (1/sin^2 x)
sinx / sin^2 x
1/ sin x
csc x

QED!


______________________________________...
1 + sin A = cos^2 A / ( 1 - sin A)

work with left side:
plug in Pyth ID that cos^2 A + sin^2 A = 1 ==> cos^2 A = 1 - sin^2 A
cos^2 A / ( 1 - sin A)
(1- sin^2 A) / (1 - sin A) ==> factor the difference of two squares
(1- sin A) (1+sin A) / (1-sin A)
1 + sin A

QED!

Verifying trig identities?

I don't see how you got:
(cos^2 / sin^2) - (1/sin^2)

(1 - cos) / (1 + cos)
multiply the top and bottom by (1 - cos)
(1 - cos)^2 / (1 - cos^2)
(1 - 2cos + cos^2) / (sin ^2)
1/sin^2 - 2cos/sin^2 + cos^2/sin^2
csc^2 - 2(cos/sin)(1/sin) + cot^2
csc^2 - 2(cot)(csc) + cot^2
(csc - cot)^2
--------------------------------------...
For #2...
Get a common denominator (tan - sec)(tan + sec)

[1(tan + sec) + 1(tan - sec)] / [(tan + sec)(tan - sec)]
(2tan) / (tan^2 - sec^2)
(2tan) / [(-1)(sec^2 - tan^2)]
2 tan / (-1)(1)
-2tan

Help verifying the trig identity?

I don't have theta on my keyboard, so I'll use ß (beta) instead.

You have: (cotß/cosß) + (secß/cotß).

Using the ordinary rules for adding fractions, we get:
(cot²ß + cosß.secß) / cosß.cotß.

Now cosß.secß ≡ 1 and (1 + cot²ß) ≡ cosec²ß,
so now we have: cosec²ß / cosß.cotß = (cosec²ß / cosß).(1/cotß),
which reduces to: (cosec²ß / cosß).(sinß/cosß) = (1 / sin²ß). (1/cosß).(sinß/cosß),
and that reduces to: (1/sinß).(1/cos²ß) = cosecß.sec²ß, as required.

Help!! on verifying trig identity?

The unique thing about hyperbolic functions is that they mirror almost exactly their regular counterparts,
with one exception: cosh²x -sinh²x = 1

Now, take coshx - sinhxtanhx and turn it into coshx - sinhxsinhx/coshx

Then this becomes (cosh²x -sinh²x)/coshx. So, along with the tanhx changed, your problem becomes:

=[sinhx/coshx]/ (cosh²x -sinh²x)/coshx
=[sinhx/coshx]*coshx/( cosh²x -sinh²x)
=[sinhx/coshx]*coshx/1 ==> because cosh²x -sinh²x = 1
=sinhx

I need help verifying my trig identities, i suck at it!!!?

(1+cosx + 1 - cos x)/((1-cosx)(1+cosx))
= 2 /(1-cos^2x)
= 2/ sin^2 x
= 2 csc^2 x

sin a (sin a/cos a + cos a/sin a)
=sin a (sin^2 a + cos^2 a)/(sin a cos a)
=sin a/(sin a cos a)
=1/cos a
= sec a

Verifying Trig Identities Please Help!!!?

So your probably thinking that this is for homework...well its not, I have a test tomorrow and I need to understand a few trig identities that i've been trying to figure out for 3 days. Thanks for your help!

θ= theta/variable

(sec^4 θ) - (sec^2 θ) = (tan^4 θ) + (tan^2 θ)

3sin^2 θ + 4cos^2 θ = 3 + cos^2θ

9sec^2 θ - 5tan^2 θ = 5 + 4sec^2 θ

Help Verify a Trig. Identity?

4tanx = [4tanx - 4tan^3(x)] / [1 - 6tan^2(x) + tan^4(x)]

This is not an identity, so you shouldn't be able to prove it.

Here's how you can see that it is not true:

suppose x is 45 degrees. Then tan x = 1
left hand side = 4 But the numerator of the right hand side is (4-4)=0

Maybe you made a mistake typing the problem?

As written, the problem only involves tan(x), no multiple angles are involved.

Need a bit of help verifying a Trig. Identity..?

The solution of the problem lies in the fact that Sin²θ + Cos²θ = 1 but the resolution path you have chosen is probably not the best one. Actually, (2aSinθCosθ)² is zero only when θ is a multiple of pi/2. That is 0, pi/2, pi, 3*(pi/2), 2*pi, etc.
You can use the sin and cos of 2θ to solve your problem. Or otherwise you develop the equation and then regroup.
One solution is the following:
Let A = (2aSinθCosθ)² + a²(Sin²θ - Cos²θ)²
We know that 2sinθcosθ = sin (2θ)
And cos²θ - sin²θ = cos (2θ)
Then A is written like:
A = (a sin(2θ))² + a²(- cos (2θ))² = a²sin²(2θ)+a²(cos (2θ))²
If we factor a² then A is:
A = a² [sin²(2θ)+cos² (2θ) ] and since sin²x + cos²x = 1 for any x
Then A = a²
Which needed to be proved

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