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Question

The intensity I of light emitted by a distant pulsar was observed over a three-month period and found to vary according to the formula I = -0.019t² + 2.131t + 15.4, where t is the number of days into the observation period. How many days into the oberservation period was the pulsar's intensity greatest?

75

56

39

47

24

Answer 1

For f(x) = ax² + bx + c the maximum of minimum occurs at x = -b. 2a.

In this case, t = -2/3 / 2(-0.019)

Can you simplify and answer?