Question

If cos 9a = sin ɑ and 9ɑ < 90° , then the value of tan 5ɑ is

• A. 1/√3
• B. √3
• C. 1
• D. 0

Answer 1

Answer:

C. 1

cos (90-x) = sin x cos 9ɑ = sin ɑ cos 9ɑ = cos(90-ɑ) 9ɑ+2 = 90 10ɑ = 90 ɑ = 9 tan 5ɑ = tan (5 x 9) = tan 45 =1