IMAGINARY Function in ONLYOFFICE Spreadsheet Editor: Imaginary Coefficient

Extract the numeric coefficient b multiplying the imaginary unit from a+bi or a+bj. Its exact current English-reference syntax is =IMAGINARY(inumber). This is documented in the official ONLYOFFICE IMAGINARY function reference, checked 2026-10-13 UTC. Any square brackets in the syntax indicate an optional argument; they are not characters to enter in your formula.

Evidence boundary: Vendor claim checks cover purpose/arguments/current documentation; sample results are separately computed mathematical predictions and were not observed in ONLYOFFICE.

=IMAGINARY(inumber)

Argument rule: One required input; no optional argument or default is documented. Numbers with an imaginary unit should use lowercase i or j as specified by the vendor; direct literal coercion beyond the documented notation is not guaranteed. Do not confuse English argument separators with decimal separators.

In a new worksheet, type the following records. The numbers in B and C must be numeric cells; D contains a lowercase text suffix (i or j). Type the headers into row 1 and the data into rows 2–9. Leave columns E onward empty until entering the formulas. This dataset is original teaching data and does not depend on a downloaded example file.

Select E2 (outside the input table) and enter =COMPLEX(B2,C2,D2). Fill E2 down through E9. This uses the documented three-argument form and lets every later example read the same complex-number cells. If the calculated text contains a simplified zero term, compare the mathematical number rather than presuming a precise string-rendering convention—the official function pages do not specify all serialization cases. Do not paste explanatory table labels into numeric fields.

Use the shared B2:D9 input table and create the complex-number column E with =COMPLEX(B2,C2,D2) filled down. In F2 type =IMAGINARY(E2) and fill down through F9. The intended output is the coefficient, not a string containing i or j.

Check the sign: For E4, zero real plus −2j is not positive two; the coefficient remains −2. For E3, the real component is −5 but the imaginary coefficient is +12. Do not mistake the sign of the real part for the sign of the imaginary part.

Inline formulas and a numeric cross-check

=IMAGINARY(COMPLEX(2,7,"j")) has expected output 7; =IMAGINARY(COMPLEX(2,-7,"i")) has expected output −7. Lowercase i and j are both supported as COMPLEX suffixes per its official reference. These nested expressions avoid ambiguity about typing a complex value as plain text.

For a direct form =IMAGINARY("3-4i"), the coefficient mathematically equals −4. The vendor describes complex inputs in x+yi / x+yj notation but doesn’t specify every text-coercion case; do not claim this direct literal was natively executed. Prefer COMPLEX if an imported literal fails.

To find the net imaginary coefficient of two signals, use =IMAGINARY(E2)+IMAGINARY(E4). Rows 2 and 4 represent imaginary coefficients +4 and −2, so the expected numeric result is 2. This is a calculation on extracted coefficients, not the same as summing arbitrary text strings containing letters.

To classify whether reactance is capacitive or inductive under a convention that labels negative imaginary values as capacitive, use:

=IF(IMAGINARY(E4)<0,"Negative imaginary component","Zero or positive imaginary component")

Expected message for E4: Negative imaginary component. The engineering interpretation depends on the user’s chosen circuit sign convention; the formula itself only tests a number. For the logical function’s argument rules, consult ONLYOFFICE’s IF reference.

Rebuild check: =COMPLEX(IMREAL(E2),IMAGINARY(E2),"i") should represent 3+4i. If an abbreviated display differs (i vs 1i, for instance), compare the numeric coefficients using IMREAL and IMAGINARY rather than text equality.

• IMAGINARY is not the imaginary unit itself and is not a Boolean test. It returns the signed numeric coefficient b, while IMREAL returns a.
• The function has exactly one documented required argument and no documented default. =IMAGINARY() is outside that syntax.
• The current article describes x+yi and x+yj. Invalid or malformed text, unsanctioned suffix case, thousands separators embedded in text, and excess whitespace are not fully specified; don’t invent a particular error label.
• A spreadsheet column formatted as text may store a literal rather than a calculated COMPLEX expression. Confirm E cells begin with = when generated from formulas.
• An expected zero coefficient for a purely real value is a mathematical fact; precise native behaviour for an arbitrary non-complex numeric scalar passed directly has not been independently tested here. Use COMPLEX(8,0) for the controlled example.

To isolate a mismatch: (1) verify numeric B and C; (2) compute the simple =COMPLEX(3,4) control; (3) evaluate =IMAGINARY(COMPLEX(3,4)), expecting 4; (4) inspect D for lowercase suffix; (5) identify your Docs or Desktop build and formula language. No screenshot or error-code outcome is inferred.

In the current ONLYOFFICE Spreadsheet Editor Help Center, these functions appear in the Engineering group. To locate them, use Formula → More functions → Engineering, or the Insert Function dialog and search for the exact English name. You can also type formulas directly, starting with =. This navigation and keyboard entry method are documented by the official Insert Functions guide (checked 2026-10-13).

All formulas here use the official English names and comma-delimited syntax. The ONLYOFFICE Advanced Settings reference explains that formula language and regional settings can vary. If your editor displays a translated function name or expects another list separator, use its formula assistant rather than blindly substituting punctuation. Decimal commas and argument separators are separate regional concerns. In example formulas, literal complex numbers and the suffix are text in double quotes; unquoted entries such as 3+4i are not equivalent to a quoted text literal.

Edition and version applicability

The current unversioned ONLYOFFICE Docs Help Center documents this function. That verifies present official documentation, not a first-supported version, successful execution in every deployed Docs server, or equivalent outcomes in all versions of Desktop Editors. The ONLYOFFICE Docs changelog and Desktop Editors changelog were consulted on 2026-10-13; neither was used to infer an undocumented first introduction release for this function. Native tests on identified Docs/web and Desktop versions are still required, especially for edge-case parsing, exact error text, and round-trip formatting. Excel, Google Sheets, other spreadsheet products and cmath are not evidence of ONLYOFFICE’s native behaviour.

Verification: Argument definitions and purposes come from the linked official references. Expected values were independently calculated. Native ONLYOFFICE Docs web or Desktop execution, historical-edition testing, localized syntax, exact errors and output formatting were not tested.

• ONLYOFFICE IMAGINARY function: primary syntax and purpose.
• ONLYOFFICE Insert Functions: engineering category and how to enter formulas.
• ONLYOFFICE Spreadsheet Editor Advanced Settings: formula language and region.
• ONLYOFFICE Docs changelog: product release history, not proof of this function’s introduction.
• ONLYOFFICE Desktop Editors changelog: independent desktop release history.
• Related official references: COMPLEX, IMREAL, IMABS, IMARGUMENT.