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(cosalpha+cosbeta)^2+(sinalpha-sinbeta)^...

`(cosalpha+cosbeta)^2+(sinalpha-sinbeta)^2=4cos^2(alpha+beta)/2`

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If A=[(0,sin alpha, sinalpha sinbeta),(-sinalpha, 0, cosalpha cosbeta),(-sinalpha sinbeta, -cosalphacosbeta, 0)] then (A) |A| is independent of alpha and beta (B) A^-1 depends only on beta (C) A^-1 does not exist (D) none of these

If cosalpha+cosbeta=a, sinalpha+sinbeta=b, then cos(alpha+beta) is equal to (A) (2ab)/(a^2+b^2) (B) (a^2+b^2)/(a^2-b^2) (C) (a^2-b^2)/(a^2+b^2) (D) (b^2-a^2)/(b^2+a^2)

If cos alpha+cos beta=0=sin alpha+sinbeta, then cos2alpha+cos 2beta=

(sinalpha cos beta+cos alpha sin beta)^2+(cos alpha cos beta-sin alpha sin beta)^2=1

Prove that 2sin^(2)beta+4cos(alpha+beta)sin alpha sin beta+cos2(alpha+beta)=cos2 alpha

If cosalpha+cosbeta=0=sinalpha+sinbeta , then cos2alpha+cos2beta=?

For all value of alpha,beta,gamma prove that ,cosalpha+cosbeta+cosgamma+cos(alpha+beta+gamma)=4cos(alpha+beta)/2*cos(beta+gamma)/2*cos(gamma+alpha)/2

Show that: sin^2 alpha + sin^2 beta + 2sinalpha sinbeta cos(alpha+beta)=sin^2 (alpha+beta)

If the lines x(sinalpha+sinbeta)-ysin(alpha-beta)=3 and x(cosalpha+cosbeta)+ycos(alpha-beta)=5 are perpendicular then sin2alpha+sin2beta is equal to:

Evaluate : Delta=|{:(0,sinalpha,-cosalpha),(-sinalpha,0,sinbeta),(cosalpha,-sinbeta,0):}| .

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