Question

1-sin4A /cos4A
= 1 + 2tan2A​

Answer 1

Step-by-step explanation :

(1 - Sin⁴A) / Cos⁴A

= (1/Cos⁴A) - (Sin⁴A/Cos⁴A)

= Sec⁴A - Tan⁴A

= (Sec²A)² - (Tan²A)²

= (Sec²A + Tan²A) (Sec²A - Tan²A)

//Remember Sec²A - Tan²A = 1 and Sec²A = 1 + Tan²A

= 1 + Tan²A + Tan²A

= 1 + 2Tan²A

= R.H.S