$2x +y = 20~~....(i)\\\\6x -5y = -4~~....(ii)\\\\\\\text{Multiply equation (i) by 3:}\\\\6x +3y = 60~~...(iii)\\\\(iii)-(ii):\\\\6x+3y - 6x+5y = 60-(-4)\\\\\implies 8y = 60+4 = 64\\\\\implies y = \dfrac{64}8\\\\\implies y = 8\\\\\\\text{Substitute y =8 in equation (i):}\\\\2x+8 =20\\\\\implies 2x = 20-8 = 12\\\\\implies x = \dfrac{12}2 = 6\\\\\text{Hence (x,y) = (6, 8)}$

4 0

2 years ago

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The radius of a circular disk is given as 24 cm with a maximum error in measurement of 0.2 cm. (a) Use differentials to estimate

hoa [83]

Answer:

9.60πcm²

Step-by-step explanation:

Area of circular disk, A = πr²

Differntiate A with respect to r

dA/dr = π * (2r^(2-1)) /(2-1) + C

dA/dr = π * 2r/1

dA/dr = 2πr

dA = 2πr * dr

dA = 2πrdr

dA = maximum error ; dr= Error in measurement = 0.2 cm ; r = radius = 24cm

dA = 2π * 24 * 0.2

dA = 9.60πcm²

3 0

2 years ago