Let \(M_2(\mathbb {R})\) be the set of all \(2\times 2\) matrices with real coefficients, and identify it with \(\mathbb {R}^4\) in the usual way. Let \(SL(2,\mathbb {R})\) be the subset of \(M_2(\mathbb {R})\) consisting of those matrices with determinant equal to one.
(a) Show \(SL(2,\mathbb {R})\) is a submanifold of \(M_2(\mathbb {R})\).
(b) Exhibit the tangent space to \(SL(2,\mathbb {R})\) at the identity matrix.