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                                                                    EXHIBIT 3(i)



            FOURTH AMENDED AND RESTATED CERTIFICATE OF INCORPORATION
                                OF SYNOPSYS, INC.
                             a Delaware Corporation


                         (Pursuant to section 245 of the
                        Delaware General Corporation Law)


               Synopsys, Inc., a corporation organized and existing under the
General Corporation Law of the State of Delaware (the "General Corporation Law")
does hereby certify that:

               FIRST: The name of the Corporation is Synopsys, Inc. and that the
Corporation was originally incorporated on May 7, 1987 under the name Optimal
Solutions, Inc. (Delaware) pursuant to the General Corporation Law; and

               SECOND: The following restates in its entirety the Corporation's
Certificate of Incorporation as amended by the Board of Directors of the
Corporation in December 1998 and by the stockholders of the Corporation at their
regular meeting held March 1, 1999 in accordance with the provisions of Section
242 and 245 of the General Corporation Law:


                                    ARTICLE I

               The name of the corporation (herein called the "Corporation") is
SYNOPSYS, INC.

                                   ARTICLE II

               The address of the registered office of the corporation in the
State of Delaware is 1209 Orange Street, in the City of Wilmington, County of
New Castle. The name of its registered agent at such address is The Corporation
Trust Company.

                                   ARTICLE III

               The nature of the business or purposes to be conducted or
promoted is to engage in any lawful act or activity for which corporations may
be organized under the General Corporation Law of Delaware.


                                   ARTICLE IV

               A. Classes of Stock. This Corporation is authorized to issue two
classes of stock to be designated, respectively, "Common Stock" and "Preferred
Stock." The total number of shares that the Corporation is authorized to issue
is Two Hundred Two Million (202,000,000), par value of one cent ($.01) per
share.


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Two Hundred Million (200,000,000) shares shall be Common Stock and Two Million
(2,000,000) shares shall be Preferred Stock.

               B. Rights, Preferences and Restrictions of Preferred Stock. The
Preferred Stock authorized by this Fourth Amended and Restated Certificate of
Incorporation may be issued from time to time in series. The Board of Directors
is hereby authorized to fix or alter the rights, preferences, privileges and
restrictions granted to or imposed upon any series of Preferred Stock, and the
number of shares constituting any such series and the designation thereof, or of
any of them. Subject to compliance with applicable protective voting rights that
have been or may be granted to the Preferred Stock or series thereof in
Certificates of Determination or the Corporation's Certificate of Incorporation
("Protective Provisions"), but notwithstanding any other rights of the Preferred
Stock or any series thereof, the rights, privileges, preferences and
restrictions of any such additional series may be subordinated to, pari passu
with (including, without limitation, inclusion in provisions with respect to
liquidation and acquisition preferences, redemption and/or approval of matters
by vote or written consent), or senior to any of those of any present or future
class or series of Preferred or Common Stock. Subject to compliance with
applicable Protective Provisions, the Board of Directors is also authorized to
increase or decrease the number of shares of any series, prior or subsequent to
the issue of that series, but not below the number of shares of such series then
outstanding. In case the number of shares of any series shall be so decreased,
the shares constituting such decrease shall resume the status that they had
prior to the adoption of the resolution originally fixing the number of shares
of such series.

               C. Common Stock.

               1. Dividend Rights. Subject to any preferential dividend rights
applicable to the shares of the Preferred Stock, the holders of shares of the
Common Stock shall be entitled to receive such dividends as may be declared from
time to time by the Board of Directors.

               2. Liquidation Rights. In the event of any voluntary or
involuntary liquidation, dissolution or winding up of the Corporation, after
distribution in full of the preferential amounts to be distributed to the
holders of shares of the Preferred Stock, the holders of shares of the Common
Stock shall be entitled to receive all of the remaining assets of the
Corporation available for distribution to its stockholders, ratably in
proportion to the number of shares of the Common Stock held by them.

               3. Redemption. The Common Stock is not redeemable.


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               4. Voting Rights. The holders of shares of Common Stock shall be
entitled to vote on all matters at all meetings of the stockholders of the
Corporation and shall be entitled to one vote for each share of Common Stock
entitled to vote at such meeting.


                                    ARTICLE V

               Except as otherwise provided in this Fourth Amended and Restated
Certificate of Incorporation, in furtherance and not in limitation of the powers
conferred by statute, the Board of Directors is expressly authorized to make,
repeal, alter, amend and rescind any or all of the Bylaws of the Corporation.


                                   ARTICLE VI

               The number of directors of the Corporation shall be fixed from
time to time by a Bylaw or amendment thereof duly adopted by the Board of
Directors or by the stockholders.


                                   ARTICLE VII

               Elections of directors need not be by written ballot unless the
Bylaws of the Corporation shall so provide.


                                  ARTICLE VIII

               Meetings of stockholders may be held within or without the State
of Delaware, as the Bylaws may provide. The books of the Corporation may be kept
(subject to any provision contained in the statutes) outside the State of
Delaware at such place or places as may be designated from time to time by the
Board of Directors or in the Bylaws of the Corporation.


                                   ARTICLE IX

               No action may be taken by the stockholders of the Corporation
without a meeting, and no consents in lieu of a meeting may be taken pursuant to
Section 228 of the Delaware General Corporation Law.


                                    ARTICLE X

               A director of the Corporation shall not be personally liable to
the Corporation or its stockholders for monetary damages for breach of fiduciary
duty as a director, except for liability (i) for any breach of the director's
duty of loyalty to


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the Corporation or its stockholders, (ii) for acts or omissions not in good
faith or that involve intentional misconduct or a knowing violation of law,
(iii) under Section 174 of the Delaware General Corporation Law, or (iv) for any
transaction from which the director derived any improper personal benefit. If
the Delaware General Corporation Law is hereafter amended to authorize, with the
approval of a corporation's stockholders, further reductions in the liability of
the corporation's directors for breach of fiduciary duty, then a director of the
corporation shall not be liable for any such breach to the fullest extent
permitted by the Delaware General Corporation Law as so amended. Any repeal or
modification of the foregoing provisions of this Article X by the stockholders
of the Corporation shall not adversely affect any right or protection of a
director of the Corporation existing at the time of such repeal or modification.


                                   ARTICLE XI

               The Corporation reserves the right to amend, alter, change or
repeal any provision contained in this Fourth Amended and Restated Certificate
of Incorporation, in the manner now or hereafter prescribed by statute, and all
rights conferred upon stockholders herein are granted subject to this
reservation.

               IN WITNESS WHEREOF, SYNOPSYS, INC. has caused this Fourth Amended
and Restated Certificate of Incorporation to be signed by its President and
Chief Operating Officer and attested to by its Assistant Secretary this 16 day
of April, 1999.



                                   SYNOPSYS, INC.



                                   /s/ Chi-Foon Chan
                                   --------------------------------------
                                   CHI-FOON CHAN
                                   President
                                   Chief Operating Officer


ATTEST:



/s/ Steven K. Shevick
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STEVEN K. SHEVICK
Assistant Secretary


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