|a+b|? & gt 1
Answer? +2a? b+b? & gt 1
| One |? +2|a|? |b|? cosθ+| b | & gt; 1
cosθ& gt; -1/2, θ∈ [0,2π/3], P 1 is true.
2.|a-b| > 1,
|a-b|? & gt 1
Answer? -2a? b+b? & gt 1
| One |? -2|a|? |b|? cosθ+| b | & gt; 1
cosθ& lt; 1/2, θ∈(π/3, π), P4 is true.
choose one