Question 简化表达式 −cos(2x) 求值 sin2(x)−cos2(x)使用 sin2t=1−cos2t 变换表达式 1−cos2(x)−cos2(x)把各项相减 1−2cos2(x)变换表达式 More Steps 求值 −2cos2(x)使用 2cos2t=cos(2t)+1 变换表达式 −2×21+cos(2x)消除公因数 2 −1×(1+cos(2x))乘以项 −(1+cos(2x))计算 −1−cos(2x) 1−1−cos(2x)Solution −cos(2x) Show Solution 将表达式因式分解 (sin(x)+cos(x))(sin(x)−cos(x)) 求值 sin2(x)−cos2(x)Solution (sin(x)+cos(x))(sin(x)−cos(x)) Show Solution
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