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In /\ABC,Prove that a cos A + b cos B + ...

In `/_\ABC`,Prove that a cos A + b cos B + c cos C = 2a sin B sin C

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UNITED BOOK HOUSE-MODEL QUESTION PAPERS-SET 13-EXERCISE
  1. The coefficient of three consecutive terms in the expansion of (1+x)^n...

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  2. Show that the straight line (a + 2b) x + (a -3b)y + b -a = 0 always p...

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  3. Find the equations of straight line which are perpendicular to the str...

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  4. y = 2x is a chord of the circle x^2 + y^2 -10 x = 0. Find the equation...

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  5. Find the ratio in which the plane 2x + 2y - 2z = 1 divides the line se...

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  6. Evaluate :lim(xrarroo)[(1^(1//x)+2^(1//x)+3^(1//x))/3]

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  7. Differentiate x^(-2/3) with respect to x, with behalf of definition.

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  8. Prove that sqrt3is irrational, (use the method of contradiction)

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  9. If x and y are odd integers, then xy is also an odd integer r examine ...

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  10. The probability of occurrence of at least one event of two events X an...

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  11. If the co-efficient of variation of two frequeny distribution are 58% ...

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  12. Prove that (sec8theta-1)/(sec4theta-1)=(tan8theta)/(tan2theta)

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  13. In /\ABC,Prove that a cos A + b cos B + c cos C = 2a sin B sin C

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  14. If a1,a2,a3,...,aaare in A.P then show that 1/(a1a2)+1/(a2a3)+1/(a3a4)...

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  15. Solve x^2 -(7 -i)x + (18 -i) = 0 and hence prove that the roots are no...

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  16. The Indian cricket eleven is to be selected out of 15 players. 6 of th...

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  17. Draw the graph and' find the common region of the system of following ...

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  18. If the pointP(at^2,2at) is a end point of a chord of the parabolay^2=...

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  19. In a hyperbola, (a) centre is origin (b) transverse axis along-with x ...

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  20. find the equation of the ellipse whose eccentricities is 1/2, focus i...

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