SOLUTION: sec theda - cos theda = sin thedacos theda

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Question 358056: sec theda - cos theda = sin thedacos theda
Found 3 solutions by Fombitz, stanbon, nyc_function:
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!

Minor correction: It's theta not theda.
What's your question though?
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sec%28theta%29-cos%28theta%29=sin%28theta%29cos%28theta%29

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
sec theda - cos theda = sin thedacos theda
------------------
sec - cos = sin*cos
---
(1/cos) - cos = sin*cos
-----
(1-cos^2)/cos = sin*cos
----
sin^2/cos = sin*cos
---
sin^2 = sin(cos^2)
-------
The original equation is not an identity.
----------------
There is no value of theda that will make
the original equation true.
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Cheers,
Stan H.

Answer by nyc_function(2741) About Me  (Show Source):
You can put this solution on YOUR website!
The word is theta not theda.

You did not say whay exactly needs to be done here but my guess is proving trig identities.

When proving trig identities, convert everything to sine and cosine.

secθ - cosθ = sinθcosθ

We know that secθ = 1/cosθ.

So, replace sine theta with 1/cos theta.

1/cosθ - cosθ = sinθcosθ

On the left side, we simply apply the rules for subtraction of fractions.

The left side becomes (1 - cos^2θ)/cosθ.

The equation now looks like this:

(1 - cos^2θ)/cosθ = sinθcosθ

Can you take it from here?