Question

In the following diagram, triangle ABC is right-angled and D is the midpoint of BC. Angle DAC=30 degrees and angle BAD=x degrees. Denoting the length of AD by L. I) express each of ac and Bc exactly in terms of L, and show that AB =1/2Lsquare root of 7. Iii) show that x= tan power of -1 2/square root of 3