The company acquired a machine on January 1 at an original cost of $100,000. The machine’s estimated residual value is $10,000, and its estimated life is four years. The company uses double-declining-balance depreciation and switches to straight-line in the final year of the machine’s life. Compute

(1) Depreciation expense for each year of the machine’s 4-year life and

(2) Book value at the end of each year of the machine’s 4-year life.