He4llo, samdmansam!
Another approach to (a) . . .
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When we have: .
. . there is a procedure we can follow.
There are three cases to consider . . .
[1] Even secant, any tangent.
Example: .
We have: .
. . . . . . . . . .
. . . . . change to tangents
. . . . . . . . .
. .
. . And we have: .
[2] Odd tangent, any secant
Example: .
We have: .
. . . . . . . . . . . . . .
. . . . . . . . . change to secants
. . . . . . . . . . . .
. .
. . And we have .
[3] Odd secant, even tangent
This is the dreaded case, where a formula must be known
. . or it must be derived.
. .
and a reduction formula is also recommended.