William C. answered 10/04/23
Experienced Tutor Specializing in Chemistry, Math, and Physics
1) Suppose f(x), g(x), and h(x) are continuous functions such that g(−1)=5, h(−1)=3 and limx→−1 ((f(x))2 − 3g(x)/ 5h(x)))=14. If f(x) is an odd function with f(1) > 0, find f(−1).
If limx→−1 ((f(x))2 − 3g(x))/5h(x) = 14
then ((f(–1))2 − 3g(–1))/5h(–1) = ((f(–1))2 − 3(5))/5(3) = ((f(–1))2 − 15)/15 = 14
Multiplying both sides by 15 gives
f(–1))2 − 15 = 15×14 = 210
Adding 15 to both sides gives
(f(–1))2 = 210 + 15 = 225
Taking the square root to both sides gives
f(–1) = ±√(225) = ±15
Now here's the key point
If f(x) is an odd function with f(1) > 0, then f(−1) < 0.
So f(–1) = –15
2) Assuming I'm interpreting the piecewise function correctly as
f(x) = (√(x2 + 3x – 2))/(x –1) {x ≠ 1}; f(x) = –1 {x = 1}
discontinuities:
a. f(x) →∞ as x → 1 from the right; this is an infinite discontinuity
b. √(x2 + 3x – 2) is undefined for ½(–3 –√17) < x < ½(–3 +√17) because x2 + 3x – 2 is negative between
½(–3 –√17) and ½(–3 +√17).
This seems like a discontinuity to me, but I I don't know what-type/what-it's-called.
c. I'm not seeing either a removable discontinuity or a jump discontinuity.