Question

Precalculus - Cofunction Identities

Answer 1

\[\cos (\frac{ \pi }{ 2 } - A) = \sin (\frac{ \pi }{ 4 })\]

Forget how to do these.

Answer 2

Need to find A

Answer 3

I know we use:

\[\cos (\frac{ \pi }{ 2 } - \theta ) = \sin \theta\]

Answer 4

In this case, A is the complement of \(\dfrac{\pi}{4}\)

Answer 5

\[A + \frac{ \pi }{ 4 } = \frac{ \pi }{ 2 }\] ?

Answer 6

Correct.

Answer 7

Wait so A is pi/4?

Answer 8

Yes

Answer 9

That's it ? lol

Answer 10

Yep

Answer 11

But in general, the angles of cofunctions are complements of each other.

Answer 12

So in the case of: \[\sec (\frac{ \pi }{ 2 } - A) = \csc (\frac{ \pi }{ 7 })\]
\[A + \frac{ \pi }{ 7 } = \frac{ \pi }{ 2 }\]

Answer 13

Yes