Prove that 2 tan-1 a-ba+b tan θ2 = cos-1 a cos θ+ba+b cos θ

Prove that $2 \tan^{- 1} (\sqrt{\frac{a - b}{a + b}} \tan \frac{θ}{2}) = \cos^{- 1} (\frac{a \cos θ + b}{a + b \cos θ})$

Matching exercise

Match the items on the right to the items on the left.

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

Step 7

Step 8

Step 9