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If A,B,(A - B)are positive acute angles,...

If A,B,(A - B)are positive acute angles, then prove that geometrically : cos (A - B) = cos A cos B + sin A sin B

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UNITED BOOK HOUSE-MODEL QUESTION PAPERS-SET 3-EXERCISE
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  2. In.an examination. 50%of the condidates have passed in mathematics 50%...

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  3. If A,B,(A - B)are positive acute angles, then prove that geometrically...

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  4. Show thatcos((2pi)/7)+cos((4pi)/7)+cos((6pi)/7)=-1/2

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  5. Show that a^6+a^4+a^2+1=0,when a=1/sqrt2(1+i)

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  6. Prove by mathematical induction:(3^(4n+1)+2^(2n+2))is divisible by 7.

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  7. Show that the co-efficient of the middle term of the expansion of(1+x)...

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  8. If (y/z)^a.(z/x)^b.(x/y)^c=1and a,b,c are in A.P ,show that x,y,z are ...

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  9. In /\XYZthe equation of the perpendicularbisector of XY and XZ arc x-y...

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  10. Find the distance of the point (3. 5) from the line 2x + 3y = 14measur...

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  11. The end’ points of a rod having length l are moving a long with two st...

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  12. Find the equation of a circle .which passes through (-2. 1) and touche...

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  13. Evaluate:lim(x-0)((e^x-1)log5(1+5x))/(sin^2x)

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  14. Differentiate a^x with respect to x (a> 0) with the help 1st principle...

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  15. ‘I80 is the multiple of 4 or 5 examine the validity of the compound st...

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  16. ‘x is such a real number that 4x^3 + 3x= 0, then x = O’. Find the trut...

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  17. The AM and SD of the marks obtained in the subjects' Bengali, .English...

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  18. If cosalpha=siny/sinx,cosbeta=sinz/sinxand cos(alpha-beta)=siny sinz.S...

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  19. Solve :16^(sin^2x)+16^(cos^2x)=10.[0lexlepi]

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  20. Find the common solution region by. the graphical method.3x+2yle18,x+2...

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