The equation given is for an exponential curve: d = a × bᵗ.
Step 1: Find the value of `a`.
The constant `a` is the initial value, or the y-intercept, where t=0.
Let's substitute t=0 into the equation:
d = a × b⁰
Since any number raised to the power of 0 is 1 (b⁰ = 1), the equation becomes:
d = a × 1
d = a
So, `a` is the value of `d` when t=0. Looking at the graph, the curve crosses the d-axis at 5.
Therefore, **a = 5**.
Step 2: Find the value of `b`.
Now we know the equation is d = 5 × bᵗ. We can find `b` by substituting the coordinates of another point from the curve. Let's choose a point that is easy to read accurately, for example, the point (t=2, d=20).
Substitute t=2 and d=20 into the equation:
20 = 5 × b²
To solve for b, first divide both sides by 5:
20 / 5 = b²
4 = b²
Now, take the square root of both sides:
b = √4
b = 2
(We take the positive root because the graph shows growth).
Therefore, **b = 2**.
The final equation is d = 5 × 2ᵗ. We can check this with another point, (t=3, d=40): 40 = 5 × 2³, which is 40 = 5 × 8. This is correct.