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Statement I In a triangle ABC if tan A:...

Statement I In a triangle ABC if `tan A: tan B: tan C=1 :2:3, ` then `A=45^(@)`
Statement II If `p:q:r=1:2:3,` then `p=1`

A

A. Both Statement I and Statement II are correct and Statement II is the correct explanation of Statement I

B

B. Both Statement I and Statement II are correct and Statement II is not the correct explanation of Statement I

C

C. Statement I is correct but Statement II is incorrect

D

D. Statement I is correct but Statement I is incorrect

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we will analyze both statements step by step. ### Step 1: Analyze Statement I We are given that in triangle ABC, the ratio of the tangents of the angles is: \[ \tan A : \tan B : \tan C = 1 : 2 : 3 \] Let’s denote: \[ \tan A = x, \quad \tan B = 2x, \quad \tan C = 3x \] ### Step 2: Use the Sum of Angles in a Triangle We know that the sum of angles in a triangle is: \[ A + B + C = 180^\circ \] ### Step 3: Apply the Tangent Addition Formula Using the tangent addition formula: \[ \tan(A + B) = \frac{\tan A + \tan B}{1 - \tan A \tan B} \] Since \(A + B = 180^\circ - C\), we have: \[ \tan(A + B) = -\tan C \] Substituting the values we have: \[ \tan A + \tan B = x + 2x = 3x \] \[ \tan A \tan B = x \cdot 2x = 2x^2 \] Now substituting into the tangent addition formula: \[ 3x = -\tan C = -3x \] ### Step 4: Set Up the Equation From the tangent addition formula, we have: \[ 3x = \frac{3x}{1 - 2x^2} \] Cross-multiplying gives: \[ 3x(1 - 2x^2) = 3x \] ### Step 5: Simplify the Equation Assuming \(x \neq 0\) (since angles cannot be zero in a triangle): \[ 3x - 6x^3 = 3x \] This simplifies to: \[ -6x^3 = 0 \] Thus, \(x^3 = 0\) implies \(x = 0\) is not valid. ### Step 6: Find the Values of Angles Now, we can find: \[ \tan A + \tan B + \tan C = x + 2x + 3x = 6x \] And: \[ \tan A \tan B \tan C = x \cdot 2x \cdot 3x = 6x^3 \] Using the identity: \[ \tan A + \tan B + \tan C = \tan A \tan B \tan C \] We have: \[ 6x = 6x^3 \] ### Step 7: Solve for x This gives: \[ x^3 - x = 0 \] Factoring out \(x\): \[ x(x^2 - 1) = 0 \] Thus, \(x = 0\) or \(x = 1\) or \(x = -1\). ### Step 8: Determine Valid Angles If \(x = 1\): \[ \tan A = 1 \implies A = 45^\circ \] If \(x = 0\) or \(x = -1\), those are not valid for angles in a triangle. Thus, **Statement I is true**. ### Step 9: Analyze Statement II The second statement says: If \(p : q : r = 1 : 2 : 3\), then \(p = 1\). ### Step 10: Set Up the Ratios Let’s denote: \[ p = x, \quad q = 2x, \quad r = 3x \] If \(p = 1\), then \(x = 1\) which gives: \[ q = 2 \quad \text{and} \quad r = 3 \] However, if \(x = 2\), then: \[ p = 2, \quad q = 4, \quad r = 6 \] This shows that \(p\) can take multiple values depending on the value of \(x\). Thus, **Statement II is false**. ### Conclusion - **Statement I is true**: \(A = 45^\circ\) - **Statement II is false**: \(p\) does not necessarily equal 1. ### Final Answer The correct answer is that **Statement I is true and Statement II is false**. ---
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Statement 1. In any triangle ABC,if a:b:c=4:5:6, then R:r=16:7 , Statement 2. In any triangle R/r= (abc)/(4s) (A) Both Statement 1 and Statement 2 are true and Statement 2 is the correct explanation of Statement 1 (B) Both Statement 1 and Statement 2 are true and Statement 2 is not the correct explanatioin of Statement 1 (C) Statement 1 is true but Statement 2 is false. (D) Statement 1 is false but Stastement 2 is true