Hey. The question is find the value of R and the value of A. sinx+ 2cosx = Rcos(x-A) i can find R which is square root of 5, but i keep getting 1.11 for A and the answer is 0,46 (radians) can anyone help?
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Hello Oasis1993 Originally Posted by Oasis1993 Hey. The question is find the value of R and the value of A. sinx+ 2cosx = Rcos(x-A) i can find R which is square root of 5, but i keep getting 1.11 for A and the answer is 0,46 (radians) can anyone help? $\displaystyle R\cos(x-A) = R\cos x \cos A + R \sin x \sin A=\sin x + 2\cos x$ $\displaystyle \Rightarrow R\sin A = 1,\;R\cos A = 2$ $\displaystyle \Rightarrow \tan A =\tfrac12$ $\displaystyle \Rightarrow A = 0.46...$ Grandad
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