Which of the following are NOT correct regarding the equation of tangent and normal to the curve $y =\frac{x-11}{(x-2)(x-3)}$ at the point, where it cuts the x-axis? (A) The point of contact is (11, 0). Choose the correct answer from the options given below: |
(A), (B) and (D) only (B) and (C) only (A), (C) and (D) only (C) and (D) only |
(C) and (D) only |
The correct answer is Option (4) → (C) and (D) only Given curve: $y=\frac{x-11}{(x-2)(x-3)}$ Where it cuts the x–axis: $y=0$ $\frac{x-11}{(x-2)(x-3)}=0 \Rightarrow x-11=0$ $x=11$ So point of contact = $(11,0)$ → (A) is correct. Now find slope. $y=\frac{x-11}{(x-2)(x-3)}$ Differentiate: Let $u=x-11$, $v=(x-2)(x-3)=x^{2}-5x+6$ $y'=\frac{u'v-uv'}{v^{2}}$ $u'=1$ $v'=2x-5$ $y'=\frac{(x^{2}-5x+6)-(x-11)(2x-5)}{(x^{2}-5x+6)^{2}}$ Evaluate at $x=11$: Slope of tangent: $m = \frac{72}{5184}=\frac{1}{72}$ Given option says slope = $\frac{1}{88}$ → (D) is NOT correct. Tangent at $(11,0)$: $y = \frac{1}{72}(x-11)$ $72y = x-11$ $x - 72y - 11 = 0$ → matches (B), so (B) is correct. Normal slope = $-72$ Normal equation: $y-0 = -72(x-11)$ $y = -72x + 792$ $72x + y - 792 = 0$ Given option says $72x + y - 11 =0$ → wrong constant → (C) is NOT correct. NOT correct statements: (C) and (D) |