Question

If A is an acute angle and cosA=(5/13), then the value of cosec A is .........................

Answer 1

cosA=5/13 , We know, $si{n}^2$A+$co{s}^2$A = 1 ,

Lets take sinA = x , Also cosA = 5/13 , so $co{s}^2$A= 25/169 then

Hence $x^2$+ 25/169 = 1

$x^2$= 1- 25/13 = 144/169

x = 12/13

now cosec A = 1/sinA

cosecA = 1/(12/13) = 13/12