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Pls help

Prove the trigonometric identity
csc x cos x/tan x+cot x =cos^2 x
Drag the expressions into each box to complete the proof.


Pls help Prove the trigonometric identity csc x cos x/tan x+cot x =cos^2 x Drag the-example-1
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User Ewggwegw
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2 Answers

4 votes

Answer:

Here is the proof of the trigonometric identity


(\csc x \cos x)/(\tan x + \cot x) = \cos^2 x

Given:


(\csc x \cos x)/(\tan x + \cot x)

To prove:


(\csc x \cos x)/(\tan x + \cot x) = \cos^2x

Step 1: Rewrite all trigonometric functions in terms of sine and cosine.


(\csc x \cos x)/(\tan x + \cot x) \\ = ((1)/(\sin x) \cos x)/((\sin x)/(\cos x) + (\cos x)/(\sin x)) \\ = (\cos x)/(\sin x \cdot (\sin x)/(\cos x) + \cos x \cdot (\cos x)/(\sin x)) \\ \\ = (\cos x)/((\sin^2 x + \cos^2 x)/(\sin x \cos x)) \\ \\ = (\cos x)/((1)/(\sin x \cos x)) \\ \\ = \cos x \cdot \sin x \cos x \\ \\ = \cos^2 x

Step 2:Simplify the expression.


\cos^2 x = \cos^2 x

Conclusion:Therefore,


(\csc x \cos x)/(\tan x + \cot x) = \cos^2 x.

Hence Proved:

answered
User Haseeb Khan
by
7.9k points
6 votes

Answer:


( \csc x \cos x)/(\tan x + \cot x)=\cos^2 x
\textsf{Rewrite $\csc x=(1)/(\sin x)}, \tan x=(\sin x)/(\cos x)$, and $\cot x=(\cos x)/(\sin x)$:}


\boxed{( (1)/(\sin x) \cdot \cos x)/((\sin x)/(\cos x) + (\cos x)/(\sin x))}=\cos^2 x


\boxed{((\cos x)/(\sin x))/((\sin^2 x )/(\sin x + \cos x)+(\cos^2 x )/(\sin x + \cos x))}=\cos^2 x


\boxed{((\cos x)/(\sin x))/((\sin^2 x + \cos^2 x)/(\sin x + \cos x))}=\cos^2 x


\boxed{((\cos x)/(\sin x))/((1)/(\sin x + \cos x))}=\cos^2 x


\boxed{(\cos x)/(\sin x) \cdot \sin x \cos x}=\cos^2 x


\cos^2 x=\cos^2 x

Explanation:

Given trigonometric identity:


( \csc x \cos x)/(\tan x + \cot x)=\cos^2 x


\textsf{Use the identities\;\;$\csc x=(1)/(\sin x)$\;,\;$\tan x = (\sin x)/(\cos x)$\;\;and\;\;$\cot x=(\cos x)/(\sin x)$}:


\textsf{Rewrite $\csc x=(1)/(\sin x)}, \tan x=(\sin x)/(\cos x)$, and $\cot x=(\cos x)/(\sin x)$:}


\boxed{( (1)/(\sin x) \cdot \cos x)/((\sin x)/(\cos x) + (\cos x)/(\sin x))}=\cos^2 x

Simplify the numerator and make the fractions in the denominator like fractions:


\boxed{((\cos x)/(\sin x))/((\sin^2 x )/(\sin x + \cos x)+(\cos^2 x )/(\sin x + \cos x))}=\cos^2 x


\textsf{Apply\;the\;fraction\;rule\;\;$(a)/(b)+(c)/(b)=(a+c)/(b)$\;to\;the\;denominator}:


\boxed{((\cos x)/(\sin x))/((\sin^2 x + \cos^2 x)/(\sin x + \cos x))}=\cos^2 x


\textsf{Use\;the\;identity\;\;$\sin^2x+\cos^2x=1$}:


\boxed{((\cos x)/(\sin x))/((1)/(\sin x + \cos x))}=\cos^2 x


\textsf{Apply\;the\;fraction\;rule\;\;$(a)/((b)/(c))=a \cdot (c)/(b)$}:


\boxed{(\cos x)/(\sin x) \cdot \sin x \cos x}=\cos^2 x

Cancel the common factor sin x, and apply the exponent rule aa = a²:


\cos^2 x=\cos^2 x

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