Hi. Yes CAT and TANCET have the same syllabus but different pattern and sections. CAT has 3 segments namely Verbal Ability and Reading Comprehension, Data Interpretations and Logical reasoning,  and Quantitative Ability. Whereas TANCET has 5 sections namely Reading Comprehensions, English Grammar and usage,  Quantitative Ability,  Data Sufficiency and Analysis of Business Situation. Here,  Analysis of Business Situation consists of passages related to business and questions are asked on problem solving. For someone who is preparing for CAT,  preparation of TANCET need not be done separately. Although, solving previous years TANCET question papers is recommended.