问答题(1983年全国统考

当实数t取什么值时,复数z=+i的辐角主值θ适合0≤θ≤π/4 ?

答案解析

因为复数z=+i的实部与虚部都是非负数,所以z的辐角主值θ一定适合0≤θ≤π/2.从而0≤θ≤π/4⇔0≤tanθ≤1.显然 r=|z|≠0.因为tanθ=sinθ/cosθ===,所以0≤tanθ≤1⇔0≤√(|t...

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