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Verify 1/sin(x)cos(x) - cot(x) = tan(x) with steps. Please answer quickly, thank you :)

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User Lennholm
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Answer:

True

Explanation:

We can verify the trigonometric identity:


(1)/(\sin(x)\cos(x)) - \cot(x) = \tan(x)

by finding a common denominator for the terms on the left side, then canceling factors in the numerator and denominator until we get the definition for tangent, which is:


\tan(x) = (\sin(x))/(\cos(x))

First, we can expand the term cot(x) with its definition:


(1)/(\sin(x)\cos(x)) - (\cos(x))/(\sin(x)) = \tan(x)

Next, to get a common denominator, we can multiply the cot(x) term by
(\cos(x))/(\cos(x)):


(1)/(\sin(x)\cos(x)) - \left((\cos(x))/(\sin(x))\right) \!\left((\cos(x))/(\cos(x))\right) = \tan(x)


(1)/(\sin(x)\cos(x)) - ((\cos(x))^2)/(\sin(x)\cos(x)) = \tan(x)

Then, we can combine the fractions because they have a common denominator of sin(x) cos(x):


(1 - (\cos(x))^2)/(\sin(x)\cos(x)) = \tan(x)

From here, we have to manipulate the Pythagorean Identity:


(\sin(x))^2+(\cos(x))^2=1

so that we have 1 - (cos(x))² on one side:


(\sin(x))^2=1-(\cos(x))^2

Now, we can substitute this identity into the numerator of the left side of the identity we are verifying:


((\sin(x))^2)/(\sin(x)\cos(x)) = \tan(x)

We can see that sin(x) is a common factor in the numerator and denominator, so we can cancel it from both:


(\sin(x))/(\cos(x)) = \tan(x)

Finally, we can see that the identity is true because it yields the definition of tangent.

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User Michael Tsang
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