Question

If tan5A.tan4A=1,then A is _______¡
Gujarat NTSE Stage 1 questions​

Answer 1

tanθ cotθ = 1

Similarly, as tan5A tan4A = 1

As we are dealing only with acute angles,

So, tan 4A = cot 5A

tan 4A = tan (90-5A)

4A = 90 - 5A

90° = 4A + 5A

90° = 9A

A = 10°