Topic Details (Notes format)

How to Use the Factorial Function (n!)

Subject: Mathematics

Book: Maths Mastery

The factorial of n, denoted n!, is the product of all positive integers up to n (e.g., 5!=120). Factorials appear in permutations, combinations (nCr = n! / [r!(n-r)!]), and expansions. For large n, the numbers grow rapidly. Factorials are key to gamma functions, probability distributions (Poisson), and combinatorial logic. Understanding them fosters quick problem-solving in arrangement tasks, advanced series expansions, or bridging to continuous extensions in advanced calculus or physics contexts.

Practice Questions

What is the area of a sector of a circle with radius 14 cm and central angle 90°?

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A train 120 meters long is moving at a speed of 54 km/h. How long will it take to pass a pole?

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If 3x = 81, what is the value of x?

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If a = 4 and b = 5, what is the value of (a+b)^2?

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If a + b = 10 and ab = 21, what is the value of a^2 + b^2?

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If 2x = 16, what is the value of x?

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If the ratio of two numbers is 3:5 and their HCF is 4, what are the numbers?

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If a = 2 and b = 3, what is the value of (a^2 + b^2)?

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What is the HCF of 48 and 180?

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If a+b = 10 and ab = 21, what is the value of a^3 + b^3?

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