Question

9 ,10question please solve​

Answer 1

Answer:

9. sec^4a - sec^2a = tan^4a+tan^2a

Take common sec^2a .

sec^2a ( sec^2a-1) [from the identity sec^2a-tan^2a=1]

sec^2a= 1+tan^2a and sec^2a-1=tan^2a

so, sec^2a ( sec^2a-1) = (1+tan^2a)tan^2a

= tan^2a+ tan^4a...

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