Question

sec²A + tan²A - 2sinA sec²A , expand it ?​

Answer 1

Answer:

We know, sec^2A=1+tan^2A

Now putting the value in the given equation we get,

1+tan^2A=2tanA

Now, tan^2A-2tanA+1=0

It will become, (tanA-1) ^2=0 as we know the formula (a-b) ^2=a^2–2ab+b^2.

tanA=1

tanA=tan45° (tan45°=1)

So, A=45° is the answer