Predicted 2-parameter projected 1-σ and 2-σ contours on the wCDM cosmological parameters from Table 1, for Euclid. The optimistic case, probing ℓ-modes up to 5000, is considered here. The biases in the predicted values of the cosmological parameters, that arise from neglecting the basic reduced shear and magnification bias corrections, are shown here (bottom left). The additional IA-lensing bias terms are not included. Of these, Ω_m, σ₈, n_s, Ω_DE, w₀, and w_a have significant biases of −0.53σ, 0.43σ, −0.34σ, 1.36σ, −0.68σ, and 1.21σ, respectively. Additionally, the altered contours from including the reduced shear and magnification bias corrections, and their derivatives, in the Fisher matrix calculation are also shown (top right). The contours decrease in size for the parameters Ω_b, h, n_s, w₀, and w_a. However, in the case of Ω_DE, the contours increase in size.