A geophysical forward problem is expressed as \( d = 7m_1^2 m_2 + 6m_2 \), where \( m_1 \) and \( m_2 \) represent the model parameters and \( d \) represents the data. Then, the relationship between data and model parameters is
Show Hint
Always check if the equation expresses the data directly as a function of model parameters (explicit).
Next, examine the powers of parameters: if only first powers appear, it's linear; otherwise, it is non-linear.
Step 1: Explicit vs Implicit.
The equation is given in the form
\[
d = f(m_1, m_2) = 7m_1^2 m_2 + 6m_2
\]
This shows \(d\) directly as a function of model parameters \(m_1\) and \(m_2\).
Therefore, the relation is explicit.
Step 2: Linear vs Non-linear.
A linear model means that the data is a linear combination of model parameters (\(a m_1 + b m_2 + c\)).
Here, the equation contains a quadratic term in \(m_1\):
\[
7m_1^2 m_2
\]
This introduces non-linearity.
Therefore, the relation is non-linear.
Final Conclusion:
The relationship is explicit and non-linear.
\[
\boxed{\text{Option (C)}}
\]