Please help me solve this exponential equation.

Question

Find C and a so that f(x) = Ca^x satisfies the given conditions.
f(0)=3 and f(3)=24

I got C=3 and a=2

But this is wrong because the answer is: 0,+-√3
Thank you for your help.

Answer 1

Tuan,

 

Your answer was correct so that +- radical must be an answer to some different problem.

 

To verify your answer, let's just check the given conditions.

 

f(x) = 3 (2)^x

f(0) = 3 (2)⁰ = 3 (1) = 3 , checks

f(3) = 3 (2)³ = 3 (8) = 24, checks