GuideFoot - Learn Together, Grow Smarter. Logo

In Mathematics / College | 2025-07-04

Verify that the equation is an identity.

$\frac{\cos \theta+1}{\tan ^2 \theta}=\frac{\cos \theta}{\sec \theta-1}$

To verify the identity, start with the more complicated side and transform it at each step.
$\begin{array}{l}
\frac{\cos \theta+1}{\tan ^2 \theta} \
=\frac{\cos \theta+1}{\sec ^2 \theta-1} \
=\frac{\cos \theta+1}{\square}
$\end{array}
$\tan ^2 \theta+1=\sec ^2 \theta$
$\square$

Asked by UniqueBryant

Answer (3)

To verify this identity, we will start with the more complicated side of the equation and manipulate it step by step until it matches the simpler side.
Given: tan 2 θ cos θ + 1 ​ = sec θ − 1 cos θ ​
Start with the left-hand side (LHS): tan 2 θ cos θ + 1 ​
First, remember the Pythagorean identity: tan 2 θ + 1 = sec 2 θ
Thus, we can express tan 2 θ as: tan 2 θ = sec 2 θ − 1
Substitute tan 2 θ in the LHS: sec 2 θ − 1 cos θ + 1 ​
Notice that sec 2 θ − 1 can be further simplified using the identity for tan 2 θ . This does not need further simplification as we have already substituted tan 2 θ = sec 2 θ − 1 .
Next, notice that the LHS now looks like: tan 2 θ cos θ + 1 ​
Since tan θ = c o s θ s i n θ ​ , we have tan 2 θ = c o s 2 θ s i n 2 θ ​ .
Substitute tan 2 θ with its expression in terms of sine and cosine: c o s 2 θ s i n 2 θ ​ cos θ + 1 ​ = c o s 2 θ s i n 2 θ ​ cos θ + 1 ​ = sin 2 θ cos 3 θ + cos 2 θ ​
Rearrange it to fit the RHS form:
Typically, verifying identities also involves considering other identities. Let's re-evaluate the process and for accurate simplification, focus on using fundamental transformations such as expressing all terms under a common denominator on the RHS.
Given the complexity of handling the reciprocal of trigonometric functions, trying to express one side in terms of another requires skillful manipulation which seems omitted in the simplification steps provided.
Substitute and simplify: ∵ sec θ = cos θ 1 ​
The transformation was supposed to directly apply some section transforms which also involves an approaches based on identity transformations:

sin 2 θ + cos 2 θ = 1
convert back esithers to the cos terms by simplification reducing back the terms.

The ultimate goal states succeeding conclusions via identity management ,in further simplification connects establishing equality to verify identity. Occasionally this involves direct substitutions to validate where expression tends.
Note: Checking identities typically requires thorough verification of transformations based on embedding trigonometric relationships and is done methodically while ensuring validity through algebraic and equivalent transformations throughout each step shared. Called recursively analyzing the expression alignment.

Answered by OliviaLunaGracy | 2025-07-07

We verified the identity t a n 2 θ c o s θ + 1 ​ = s e c θ − 1 c o s θ ​ by manipulating both sides using trigonometric identities and simplifications. The left-hand side was transformed to match the right-hand side, confirming they are equal. This shows the equation holds true.,
;

Answered by jacob193 | 2025-07-07

Apply the Pythagorean Identity sin 2 θ = 1 − cos 2 θ to verify that the given equation holds as long as cos θ  = 0 and sin θ  = 0 :
tan 2 θ cos θ + 1 ​ = sec θ − 1 cos θ ​ . ;

Answered by jacob193 | 2025-07-07