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JAMB UTME - Mathematics - 1983

Question 1 Report

Given that cos z = L , whrere z is an acute angle, find an expression for \( \frac{\cot z - \cosec z}{\sec z + \tan z} \)

Answer Details

Given Cos z = L, z is an acute angle
cot z - cosec z sec z + tan z  = cos z
=  cos z sin z
cosec z =  1 sin z
cot z - cosec z =  cos z sin z  -  1 sin z
cot z - cosec z =  L − 1 sin z
sec z =  1 cos z
tan z =  sin z cos z
sec z =  1 cos z  +  sin z cos z
=  1 l  +  sin z L
the original eqn. becomes
cot z - cosec z sec z + tan z  =  L − 1 sin z 1 + s i n z L
=  L ( L − 1 ) sin z ( 1 + sin z )
=  L ( L − 1 ) sin z + 1 − c o s 2 z
= sin z + 1
= 1 +  1 − L 2
=