SAT Math Multiple Choice Question 917: Answer and Explanation
1. Given the functions defined above, what is the value of (g ° h)(5)?
- A. 0
- C. 2
- D. Undefined
Correct Answer: D
Category: Passport to Advanced Math / Functions
Strategic Advice: The notation (g ° h)(x) indicates a composition of two functions, which can also be written as g(h(x)) and read as "g of h of x." It means that the output when x is substituted in h(x) becomes the input for g(x). Just remember that when working with compositions, you always start with the function that is closest to x.
Getting to the Answer: Substitute 5 for x in h(x), simplify, and then substitute the result into g(x):
Be careful-a number divided by 0 is not 0! In fact, division by 0 is not defined, so (g ° h)(5) is undefined, which is (D).