Let α, β, and γ be some angles in the first quadrant satisfying tan⁡(α+β)=15/8 and cosec⁡γ=17/8, then which of the following hold(s) good?

tan⁡(α+β)=158and cosec⁡ γ=178⇒ tan⁡ γ=815∴ α+β+γ=π2Hence, (2) is true.Also tan⁡(α+β)=tan⁡ α+tan⁡ β1−tan⁡ α tan⁡ βor   cot⁡ γ=tan⁡ α+tan⁡ β1−tan⁡ α tan⁡ βor   tan⁡ α tan⁡ β+tan⁡ β tan⁡ γ+tan⁡ γ tan⁡ α=1