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Grade 12th passTrigonometry

Prove that the value of 5cosa+3cos(a+π/3)+3 lies between -4 and 10

Profile image of Jerry Aneja
9 Years agoGrade 12th pass
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1 Answer

Profile image of Vijay Mukati
9 Years ago
Hint:
!) use the formula of cos(A+B) = cosAcosB – sinAsinB for cos (a + pi/3)
2) then convert the given eq. in the form of mcosA + nsinA + c.
3) then its range will be in between: root(m2+ n2 + c) to –root(m2 + n2 + c) .

Thanks, Vj