PYQ Vault
EbooksTutor

cos^-1 x - cos^-1(y/3) = a: value of 9x^2 - 6xy cos a + y^2

The same question, asked 2 times: 9 May 2024 S1, 14 May 2024 S2. Every wording below, oldest first.

Try each one first, then open its answer.

  1. Question 1

    9 May 2024 S1

    119
    If cos⁡−1x−cos⁡−1y3=α\cos^{-1}x-\cos^{-1}\frac{y}{3}=\alpha, where −1≤x≤1, −3≤y≤3, x≤y3-1\leq x\leq1,\,-3\leq y\leq3,\,x\leq\frac{y}{3}, then for all xx, yy, the value of 9x2−6xycos⁡α+y29x^2-6xy\cos\alpha+y^2 is equal to

    Tap an option to check your answer.

  2. Question 2

    14 May 2024 S2

    119
    If cos⁡−1x−cos⁡−1y3=α\cos^{-1}x - \cos^{-1}\frac{y}{3} = \alpha, where −1≤x≤1-1\leq x\leq1, −3≤y≤3-3\leq y\leq3, x≤y3x\leq\frac{y}{3}, then for all x,yx,y: 9x2−6xycos⁡α+y29x^2 - 6xy\cos\alpha + y^2 is equal to

    Tap an option to check your answer.