Which of the following are correctly defined functions?

Question

a) f : R → R, f(x) = 1/x^4+4 

b)f : R → R, f(x) = 1/x^4−4

c)f : R → R, f(x) = √sin^2 x

d)f : R → R, f(x) = √sin x

e)f : R → R, f(x) = 2017

Answer 1

Option D is not correct.

 

The square root function is negative between 180 and 360 

degrees (Quadrants 3 and 4)

So the function will produce imaginary and complex values.

 

Note that C is correct because squaring a negative number makes it positive.

Options A,B,C, and E are correct