回答:
说明:
我们有
什么是(sqrt(5+)sqrt(3))/(sqrt(3+)sqrt(3+)sqrt(5)) - (sqrt(5-)sqrt(3))/(sqrt(3+)sqrt (3-)SQRT(5))?
2/7我们采取,A =(sqrt5 + sqrt3)/(sqrt3 + sqrt3 + sqrt5) - (sqrt5-sqrt3)/(sqrt3 + sqrt3-sqrt5)=(sqrt5 + sqrt3)/(2sqrt3 + sqrt5) - (sqrt5 -sqrt3)/(2sqrt3-sqrt5)=(sqrt5 + sqrt3)/(2sqrt3 + sqrt5) - (sqrt5-sqrt3)/(2sqrt3-sqrt5)=((sqrt5 + sqrt3)(2sqrt3-sqrt5) - (sqrt5-sqrt3) )(2sqrt3 + sqrt5))/((2sqrt3 + sqrt5)(2sqrt3-sqrt5)=((2sqrt15-5 + 2 * 3-sqrt15) - (2sqrt15 + 5-2 * 3-sqrt15))/((2sqrt3) ^ 2-(sqrt5)^ 2)=(取消(2sqrt15)-5 + 2 * 3cancel(-sqrt15) - 取消(2sqrt15)-5 + 2 * 3 +取消(sqrt15))/(12-5)=( -10 + 12)/ 7 = 2/7请注意,如果在分母中(sqrt3 + sqrt(3 + sqrt5))和(sqrt3 + sqrt(3-sqrt5))那么答案将会改变。
你如何验证(tan ^ 2x)/(secx-1)-1 = secx?
“左手侧”= tan ^ 2x /(secx-1)-1使用标识:cos ^ 2x + sin ^ 2x = 1 => 1 + tan ^ 2x = sec ^ 2x => tan ^ 2x = sec ^ 2x -1 =>“左手侧”=(sec ^ 2x-1)/(secx-1)-1 =(取消((secx-1))(secx + 1))/取消(secx-1)-1 => secx + 1-1 =颜色(蓝色)secx =“右手侧”
你如何简化(1 / sqrt(a-1)+ sqrt(a + 1))/(1 / sqrt(a + 1)-1 / sqrt(a-1))div sqrt(a + 1)/( (a-1)sqrt(a + 1) - (a + 1)sqrt(a-1)),a> 1?
巨大的数学格式......>颜色(蓝色)(((1 / sqrt(a-1)+ sqrt(a + 1))/(1 / sqrt(a + 1)-1 / sqrt(a-1)) )/(sqrt(a + 1)/((a-1)sqrt(a + 1) - (a + 1)sqrt(a-1)))=颜色(红色)(((1 / sqrt(a-) 1)+ sqrt(a + 1))/((sqrt(a-1)-sqrt(a + 1))/(sqrt(a + 1)cdot sqrt(a-1))))/(sqrt(a) +1)/(sqrt(a-1)cdot sqrt(a-1)cdot sqrt(a + 1)-sqrt(a + 1)cdot sqrt(a + 1)sqrt(a-1)))= color(蓝色)(((1 / sqrt(a-1)+ sqrt(a + 1))/((sqrt(a-1)-sqrt(a + 1))/(sqrt(a + 1)cdot sqrt(a -1))))/(sqrt(a + 1)/(sqrt(a + 1)cdot sqrt(a-1)(sqrt(a-1)-sqrt(a + 1)))=颜色(红色) ((1 / sqrt(a-1)+ sqrt(a + 1))/((sqrt(a-1)-sqrt(a + 1))/(sqrt(a + 1)cdot sqrt(a-1) ))xx(sqrt(a + 1)cdot sqrt(a-1)(sqrt(a-1)-sqrt(a + 1))