How to solve
Dividing sin² + cos² = 1 by cos² gives the tangent-secant identity — no angle needed, just the identity.
Steps
- Square the given value.
- Add or subtract 1 per the identity.
- Leave the answer as an exact fraction.
Example
tan θ = 3/4. Find sec²θ.
- tan²θ = 9/16.
- sec²θ = 1 + 9/16 = 25/16.
Answer: 25/16
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