calculate values a and b

Question

function f(x)= 2^x/a

given points it passes through: (0, b) (2, 0.8)

Answer 1

Use the 2 given points to find a and b.

x = 0 ⇒ b = 1/a ⇒ a = 1/b ⇒

f(x) = b (2^x)

x = 2 ⇒

0.8 = b (2²)

b = 0.8/4 = 0.2

a = 1/b = 1/0.2 = 5

f(x) = 0.2 (2^x) = 2^x / 5

Test the answer.

f(0) = 0.2 = b (good)

f(2) = (0.2)(2²) = 0.8 (good)