If A = Sin-1 (cos A), what is A

If A = Sin-1 (cos A), what is A?
Thank you in advance.

A is the angle whose sine is equal to cos(A)

sinA = cosA
sinA/cosA = tanA = 1

tan45 = tan225 = 1

A = 45° or 225°

MathMom is right, sin ^-1 falls between 0 and 180 degrees

Report Abuse

A = sin⁻¹ (cosA)
sinA = cosA
A = π/4

NOTE: this is the only valid value for A
Even though A = 5π/4 is a solution to sinA = cosA, it is not a solution to A = sin⁻¹ (cosA)
since the sin⁻¹ function always returns value between −π/2 and π/2,
Therefore −π/2 ≤ A ≤ π/2

A could be anything