Question

(11) secA (1 - sin4A) - 2tan’A = 1​

Answer 1

Step-by-step explanation:

sec⁴A(1-sin⁴A)-2tan²A

=sec⁴A-sec⁴Asin⁴A-2tan²A

=sec⁴A-sin⁴A(1/cos⁴A)-2tan²A

=sec⁴A-tan⁴A-2tan²A

={(sec²A)²-(tan²A)²}-2tan²A

=(sec²A+tan²A)(sec²A-tan²A)-2tan²A

=sec²A+tan²A-2tan²A [∵, sec²A-tan²A=1]

=sec²A-tan²A

=1 (Proved)