Question
Let p(x) be a quadratic polynomial such that p(0)=1. If p(x) leaves remainder 4 when divided by x 1 and it leaves remainder 6 when divided by x + 1; then :
Options
Solution
Key Concepts and Formulas
- Quadratic Polynomial: A polynomial of degree 2, generally expressed as , where are constants and .
- Remainder Theorem: If a polynomial is divided by , the remainder is .
- System of Linear Equations: A set of two or more linear equations containing two or more variables.
Step-by-Step Solution
Step 1: Determine the Constant Term ()
We are given that . This means when we substitute into the quadratic equation, the result is 1. We can use this to find the value of . Since , we have: Now we know that .
Step 2: Apply the Remainder Theorem for Division by
We are given that leaves a remainder of 4 when divided by . By the Remainder Theorem, this means . Substituting into our expression for , we get: This gives us our first equation relating and : .
Step 3: Apply the Remainder Theorem for Division by
We are given that leaves a remainder of 6 when divided by . By the Remainder Theorem, this means . Substituting into our expression for , we get: This gives us our second equation relating and : .
Step 4: Solve the System of Linear Equations
We now have a system of two linear equations: We can solve this system by adding the two equations to eliminate : Now substitute the value of back into one of the equations to solve for . Using the first equation:
Step 5: Construct the Complete Quadratic Polynomial
We have found , , and . Therefore, the quadratic polynomial is:
Step 6: Evaluate the Given Options
Now we need to find which of the options is correct by substituting the given values into the polynomial.
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Option (A): Since , option (A) is incorrect.
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Option (B): Since , option (B) is incorrect.
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Option (C): Since , option (C) is correct.
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Option (D): Since , option (D) is incorrect.
Common Mistakes & Tips
- Sign Errors: Be careful with signs when applying the Remainder Theorem, especially when dividing by . Remember to substitute .
- Solving Linear Equations: Double-check your algebra when solving the system of equations to avoid errors in calculating and .
Summary
By applying the Remainder Theorem and solving the system of linear equations, we found the quadratic polynomial to be . Evaluating the given options, we found that , which corresponds to option (C).
The final answer is \boxed{19}, which corresponds to option (C).