I only know the exchange formula of 1-form is that $\nabla_i\nabla_j v_kdx^k-\nabla_j\nabla_iv_kdx^k=g^{lm}R_{ijkl}v_mdx^m$.
But in the below picture, only exchange formula of 1-form seems be not enough.
How to compute the second equal (part of red line) ?
