Question #3104b

1 Answer
Jun 7, 2016

C) sin(x)/cos(x)+cos(x)/sin(x)=csc(x)sec(x)

Explanation:

sin(x)/cos(x)+cos(x)/sin(x)

(Multiply by sin(x)/sin(x) and cos(x)/cos(x) to give terms a common denominator)

= sin^2(x)/(sin(x)cos(x))+cos^2(x)/(sin(x)cos(x))

=(sin^2(x)+cos^2(x))/(sin(x)cos(x))

(Apply the identity sin^2(x)+cos^2(x)=1)

=1/(sin(x)cos(x))

=1/sin(x)*1/cos(x)

(Apply the definitions csc(x)=1/sin(x) and sec(x)=1/cos(x))

=csc(x)sec(x)

=sec(x)csc(x)

Thus the answer is C.