hi,
any ideas how to answer these questions.
ocr jan08 question 9
9) i) use identity cos(A+B)to prove
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4cos(0+60)cos(0+30)= root3 - 2sin20
ii) hence find exact value82.5cos52.5
iii) solve for 0<theta<90 the equation 4cos(0+60)cos(0+30) = 1
iv) given there are no values of theta which satisfy the equation
4cos(0+60)cos(0+30) = k determine the set of values of the constant K.
cheers