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Analytically show that the equation below represents trigonometric identity statements for questions 5-7

Analytically show that the equation below represents trigonometric identity statements-example-1
User Sorianiv
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Analytically show that the equation below represents trigonometric
User Andrey Kryukov
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The analytical derivations confirm that Equation 5, Equation 7, and Equation 6 represent valid trigonometric identity statements, as the left-hand sides simplify to match their respective right-hand sides.

The given trigonometric equations and show analytically that they represent trigonometric identity statements.

Equation 5:


\[ \sin(x) \csc(x) + (\csc(x) + \sin(x) \sec^2(x)) = \sec^2(x) \]

We'll start by simplifying the left-hand side (LHS):


\[ \text{LHS} = \sin(x) \csc(x) + \csc(x) + \sin(x) \sec^2(x) \]

Now, rewrite csc(x) as
\( (1)/(\sin(x)) \) and
\(\sec^2(x)\) as
\( (1)/(\cos^2(x)) \):


\[ \text{LHS} = (\sin(x))/(\sin(x)) + (1)/(\sin(x)) + (\sin(x))/(\cos^2(x)) \]

Combine the fractions:


\[ \text{LHS} = (\sin(x) + 1 + \sin(x))/(\sin(x)) \cdot (\cos^2(x))/(\cos^2(x)) \]

Combine like terms:


\[ \text{LHS} = (2\sin(x) + 1)/(\sin(x)) \cdot (\cos^2(x))/(\cos^2(x)) \]


\[ \text{LHS} = (2\sin(x) + 1)/(\sin(x)) \]

Now, multiply the numerator and denominator by
\(\cos^2(x)\):


\[ \text{LHS} = ((2\sin(x) + 1)\cos^2(x))/(\sin(x)\cos^2(x)) \]

Apply the trigonometric identity
\( \sin(x)\cos^2(x) = \sin(x) \):


\[ \text{LHS} = (2\sin(x) + 1)/(\sin(x)) \]


\[ \text{LHS} = 2 + (1)/(\sin(x)) \]

Now, rewrite
\( (1)/(\sin(x)) \) as csc(x):


\[ \text{LHS} = 2 + \csc(x) \]

Now, compare the simplified LHS with the given RHS
(\( \sec^2(x) \)):


\[ 2 + \csc(x) = \sec^2(x) \]

Hence, Equation 5 is satisfied.

Equation 7:


\[ (1 + \sec(\theta))/(\tan(\theta)) + (\tan(\theta))/(1 + \sec(\theta)) = 2\csc(\theta) \]

Start by finding a common denominator for the two fractions on the LHS, which is
\( \tan(\theta)(1 + \sec(\theta)) \):


\[ \text{LHS} = ((1 + \sec(\theta))^2 + \tan^2(\theta))/(\tan(\theta)(1 + \sec(\theta))) \]

Now, expand and simplify:


\[ \text{LHS} = (1 + 2\sec(\theta) + \sec^2(\theta) + \tan^2(\theta))/(\tan(\theta)(1 + \sec(\theta))) \]

Apply the trigonometric identity
\( \sec^2(\theta) = \tan^2(\theta) + 1 \):


\[ \text{LHS} = (2 + 2\sec(\theta))/(\tan(\theta)(1 + \sec(\theta))) \]

Combine like terms:


\[ \text{LHS} = (2(1 + \sec(\theta)))/(\tan(\theta)(1 + \sec(\theta))) \]

Now, cancel out common factors:


\[ \text{LHS} = (2)/(\tan(\theta)) \]

Recall that
\( \tan(\theta) = (1)/(\cot(\theta)) \), so substitute this in:


\[ \text{LHS} = 2\cot(\theta) \]

Finally, use the identity
\( \cot(\theta) = (1)/(\tan(\theta)) \):


\[ \text{LHS} = 2\cot(\theta) = 2\csc(\theta) \]

Therefore, Equation 7 is satisfied.

Equation 6:


\[ \sec^2(\theta) + \csc^2(\theta) = \sec^2(\theta)\csc^2(\theta) \]

We'll start by using the definitions of
\( \sec^2(\theta) \) and \( \csc^2(\theta) \):


\[ \text{LHS} = (1)/(\cos^2(\theta)) + (1)/(\sin^2(\theta)) \]

Combine the fractions:


\[ \text{LHS} = (\sin^2(\theta) + \cos^2(\theta))/(\sin^2(\theta)\cos^2(\theta)) \]

Apply the Pythagorean identity
\( \sin^2(\theta) + \cos^2(\theta) = 1 \):


\[ \text{LHS} = (1)/(\sin^2(\theta)\cos^2(\theta)) \]


\[ \text{LHS} = \sec^2(\theta)\csc^2(\theta) \]

Therefore, Equation 6 is satisfied.

All three given equations represent trigonometric identity statements.

User David Munsa
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