Answer:
fourth option
Step-by-step explanation:
Using the trigonometric identity
cos²x + sin²x = 1
Divide all terms by cos²x
+ = which gives
1 + tan²x = sec²x
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The best and most correct answer among the choices provided by the question is <span>A.an = 20 + (n - 1)(6)</span> .<span>
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Hope my answer would be a great help for you.</span>