Answer:
y''=sec^3(x)*csc(x)+sec^2(x)*tan(x)-2cot(x)*csc(x)*sec(x)*tan(x)+cot^2(x)*csc(x)*sec(x)+csc^3(x)*sec(x)
Explanation:
we are given y= csc x sec x
We use the rule for multiplying derivatives and the knowledge that the derivative of csc is -csc*cot and the derivative of sec is sec*tan to get
csc(x)*sec(x)*tan(x)+sec(x)*-csc(x)*cot(x)
which simplifies to
csc(x)*sec(x)*tan(x)-sec(x)*csc(x)*cot(x)
Using the same rules again (in tedium so they are not listed but can be inferred) we find the second derivative is
sec^3(x)*csc(x)+sec^2(x)*tan(x)-2cot(x)*csc(x)*sec(x)*tan(x)+cot^2(x)*csc(x)*sec(x)+csc^3(x)*sec(x)