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tan25^@=a prove that (tan155^@-tan115^@)...

`tan25^@=a` prove that `(tan155^@-tan115^@)/(1+tan155^@.tan115^@)=(1-a^2)/(2a)`

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UNITED BOOK HOUSE-JADAVPUR VIDYAPITH-EXERCISE
  1. 2f(x)+3f(-x)=15-4x then [f(1)+f(-1)]=?

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  2. f(x)=a+b sinx,has max value of 7 an min value 1.Find f(pi//6)=?

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  3. tan25^@=a prove that (tan155^@-tan115^@)/(1+tan155^@.tan115^@)=(1-a^2)...

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  4. Prove that tan70^(@)=2tan50^(@)+tan20^(@).

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  5. a=(1+i)/sqrt2then a^6+a^4+a^2+1=?

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  6. x(x-3)=4,has two roots alphaand betathen alpha^2+beta^2=?

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  7. Find the area of the triangle formed by the straight lin x cosalpha+ys...

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  8. Straight line px-qy=r intercept the coordinate axis at the point (a,0)...

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  9. A relation R defined on the set of natural no as follows R={(x,y),x+5y...

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  10. cos(beta-gamma)+cos(gamma-alpha)+cos(alpha-beta)=-3/2 show that cosalp...

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  11. sintheta+sinphi=a,costheta+cosphi=bshow that tan((theta-phi)/2)=+-sqrt...

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  12. If cos theta=(acosphi+b)/(a+bcosphi)(theta,phiacute angle)show that ta...

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  13. In a triangle ABC if a cos^2(C/2)+c cos^2(A/2)=((3b)/2)show that sides...

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  14. If w be a imaginary cube root of uniyt and a+b+c=0 then show that (a+b...

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  15. An equilateral triangle in the Argan plane has vertix as z1,z2and z3wh...

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  16. If the equation x^2+px+qr=0and x^2+qx+pr=0(p!=q,r!=0)has same root the...

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  17. Prove that ^nPr=^(n-1)Pr+r^(n-1)P(r-1)(notation used are in their usua...

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  18. How many way will be made from the word JADAVPUR taking al the letters...

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  19. If a,b,c are in G.P and x,y are the arithmetic mean of a and b aand b,...

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  20. Sum of the reciprocal intercepts on the axes by a moving straight lin...

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