Question

19. If sec 4A = cosec (A -10°) and 4A is acute then A = ?
(a) 20°
(b) 25°
(c) 30°
(d​

Answer 1

Answer:

A) 20°..

here,

sec4A = cosec( A -10°)

=> cosec( 90° - 4A) = cosec( A - 10°)

on comparing both sides,

90 - 4A = A - 10

=> 90 + 10 = A + 4A

=> 100° = 5A

=> A = 100/5

=> A = 20°..

Step-by-step explanation:

$<$

formula

cosec( 90 -∅) = sec∅