Convert sin to cos on this exact page with quadrant control. The old redirect to a generic trigonometry converter hid the branch-specific answer this slug promises.
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Choose a quadrant because this conversion is branch-dependent.
The calculator rejects signs that do not fit the chosen quadrant.
Describe the task to the AI assistant and continue from the result.
Open AI assistant →Sin to Cos Calculator with Quadrant
Quick answer
A sin value alone is not always enough to choose the sign of cos. Select the quadrant so the calculator can return the correct branch and reject incompatible signs.
Quadrant sign table
| Quadrant | sin | cos | tan/cot |
|---|---|---|---|
| I | + | + | + |
| II | + | – | – |
| III | – | – | + |
| IV | – | + | – |
Common mistake
Do not assume the acute-angle answer is always correct. In quadrants II, III and IV, signs change even when the absolute value looks the same.