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三角函数辅助公式asinx+bcosx=(a~2+b~2)~(1/2)sin(x+φ)(其中tanφ=b/a),在三角恒等变形上有着非常重要的作用,特别是在求三角函数的最小正周期、最大(小)值、对称轴、对称中心、单调区间等问题上经常是用到辅助公式进行变形,同时,作为三角问题中的重要公式在历年高考中屡见不鲜.因此,学会辅助公式变得尤为重要,辅助公式中主要是φ值的确定有一定难度,其他的都好办.本文就辅助公式中φ值的确定进行了归纳总结,希望能对同学们有一定的帮助.在三角函数辅助公式asinx+bcosx中我们把sinx前面
The trigonometric function assist formula asinx+bcosx=(a~2+b~2)~(1/2)sin(x+φ) (where tanφ=b/a) plays an important role in trigonometric constant deformation. In particular, the auxiliary formulas are often used to solve the problems such as the minimum positive period, the maximum (small) value, the symmetry axis, the symmetry center, and the monotonous interval of the trigonometric function. At the same time, as an important formula in the trigonometric problem, the formula is used in the college entrance examination. It is not uncommon. Therefore, it is very important to learn the auxiliary formula. It is difficult to determine the φ value in the auxiliary formula. The others are easy to handle. This article summarizes the determination of the φ value in the auxiliary formula, hoping to be able to classmates. There is some help. In the trigonometric auxiliary formula asinx+bcosx we put sinx in front of