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標題:
maths(Variation)
發問:
1.V varies jointly as r 2 and h.Find the percentage change in V if both r and h decrease by 10%. 2.z varies directly as x and inversely as y.Find the percentage change in z if x increases by 44% and y increases by 20%.
1. V varies jointly as r 2 and h.Find the percentage change in V if both r and h decrease by 10%. let V = kr 2h ,where k is an constant the initial value of V[0] V[0] = kr2h,where k is a constant the new value of V[1] V[1] = k (0.9r)2 (0.9)h V[1] = 0.729kr2h V[1] = 0.729V[0] so,the percentage change is (V[1] - V[0] / V[0])x 100% = (0.729 - 1) x 100% = -27.1% V decreases by 27.1 % 2. z varies directly as x and inversely as y.Find the percentage change in z if x increases by 44% and y increases by 20% let z = kx/y , where k is constant z[0] = kx/y z[1] = k(144%x)/(120%y) z[1] = 1.2kx/y z[1] = 1.2z[0] so,the percentage change: ( z[1] - z[0] / z[0] )x 100% = 20% z increases by 20%.
其他解答:
maths(Variation)
發問:
1.V varies jointly as r 2 and h.Find the percentage change in V if both r and h decrease by 10%. 2.z varies directly as x and inversely as y.Find the percentage change in z if x increases by 44% and y increases by 20%.
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最佳解答:1. V varies jointly as r 2 and h.Find the percentage change in V if both r and h decrease by 10%. let V = kr 2h ,where k is an constant the initial value of V[0] V[0] = kr2h,where k is a constant the new value of V[1] V[1] = k (0.9r)2 (0.9)h V[1] = 0.729kr2h V[1] = 0.729V[0] so,the percentage change is (V[1] - V[0] / V[0])x 100% = (0.729 - 1) x 100% = -27.1% V decreases by 27.1 % 2. z varies directly as x and inversely as y.Find the percentage change in z if x increases by 44% and y increases by 20% let z = kx/y , where k is constant z[0] = kx/y z[1] = k(144%x)/(120%y) z[1] = 1.2kx/y z[1] = 1.2z[0] so,the percentage change: ( z[1] - z[0] / z[0] )x 100% = 20% z increases by 20%.
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