Trigonometry · Intermediate · 7 min

Trigonometric equations

Solving a trigonometric equation means finding every angle in the stated domain.

WHAT HAPPENS IF…How many solutions does sinθ=1 have in [0,2π)?
Interactive exploration
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Connect the picture to the ideasin⁡θ=c,0≤θ<2π\sin\theta=c,\quad 0\le\theta<2\pi

Let α=arcsin(c). The two solution families are α+2kπ and π−α+2kπ. Restrict them to the requested interval and remove duplicates. For |c|>1 there are no real solutions; this slider stays in [−1,1].

A detail that matters

A principal inverse value alone usually misses another solution.

Keep the connection going

One idea leads to another.

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