1. If y=(x+1+x2)20,d2ydx2∣ x=0 y=\left(x+\sqrt{1+x^{2}}\right)^{20}, \left.\frac{d^{2} y}{d x^{2}} \right\rvert\, x=0 y=(x+1+x2)20,dx2d2yx=0 ?
2. If area of the points A(4,2k+1),B(k,4)&C(3k+2,2k) A(4,2 k+1), B(k, 4) \& C(3 k+2,2 k) A(4,2k+1),B(k,4)&C(3k+2,2k) is 3 square unit, determine the orthocenter of the triangle. [Let, K \mathrm{K} K is an integer]
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4. If ∣x−42x2x2xx−42x2x2xx−4∣=(Bx+A)(x−A)2 \left|\begin{array}{ccc}x-4 & 2 x & 2 x \\ 2 x & x-4 & 2 x \\ 2 x & 2 x & x-4\end{array}\right|=(B x+A)(x-A)^{2} x−42x2x2xx−42x2x2xx−4=(Bx+A)(x−A)2, what is the value of A&B A \& B A&B ?
5. The radius of a semicircular tunnel is 12 m 12 \mathrm{~m} 12 m. Find the height at 10 m 10 \mathrm{~m} 10 m distance from the mid-point.