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已知sin(5π+a)=-五分之三,且a属于(2分之π,π)又tanβ=二分之一
(1)求tan(a-β)的值
(2)求sin(2a+3分之π)的值
人气:353 ℃ 时间:2020-03-28 04:14:36
解答
sin(5π+a) = sin(4π+π+a) = -sina = -3/5sina = 3/5a属于(2分之π,π)tana = -sina/√(1-sin^2a) = -(3/5)/(4/5) = -3/4tanβ = 1/2tan(a-β)= (tana - tanβ)/(1+tana tanβ) = (-3/4-1/2)/(1-3/8) = -2cos...
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