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Prove that `(b + c) cos A + (c + a) cos B + (a + b) cos C = 2s`

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CENGAGE ENGLISH-TRIGONOMETRIC FUNCTIONS-All Questions
  1. Match the statement/expressions in Column I with the statements/expres...

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  2. If (x-a)costheta+ysintheta=(x-a)cosphi+ysinphi=a and tan(theta/2)-tan(...

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  3. Prove that (b + c) cos A + (c + a) cos B + (a + b) cos C = 2s

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  4. If p=sin(A-B)sin(C-D),q=sin(B-C)sin(A-D), r=sin(C-A)sin(B-D) then (...

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  5. Let varphi,phi in [0,2pi] be such that 2costheta(1-sinphi)=sin^2theta(...

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  6. If cosA/2=sqrt((b+c)/(2c)) , then prove that a^2+b^2=c^2dot

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  7. If cosx-sinalphacotbetasinx=cosa , then the value of tan(x/2) is (a...

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  8. For 0 lt theta lt pi/2 , the solution (s) of sum(m=1)^6cos e c(theta+(...

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  9. In A B C ,if a=10 and bcotB+ c cotC=2(r+R) then the maximum area of ...

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  10. Which of the following set of values of x satisfies the equation 2^(2...

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  11. Let f(x)=a bsinx+bsqrt(1-a^2)cosx+c , where |a|<<1,b>>0 then (a) ma...

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  12. A variable triangle A B C is circumscribed about a fixed circle of uni...

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  13. Let the sum of all x in the interval [0, 2pi] such that 3 cot^(2) x+8 ...

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  14. Let P(k)=(1+cos(pi/(4k))) (1+cos(((2k-1)pi)/(4k))) (1+cos(((2k+1)pi)/...

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  15. The sides of a triangle are x^2+x+1,2x+1,a n dx^2-1 . Prove that the g...

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  16. Find the values of theta in the interval (-pi/2,pi/2) satisfying the e...

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  17. ABC is a triangle such that sin(2A+B)=sin(C-A)=-sin(B+2C)=1/2. If A,B...

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  18. Let a, b and c be the three sides of a triangle, then prove that the e...

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  19. Number of roots of the equation |sinxcosx| +sqrt(2+t a n^2x+cot^2x)=sq...

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  20. Let f:(-1,1)vecR be such that f(cos4theta)=2/(2-sec^2theta) for thet...

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