Precalc help please! | Mathematics | Page 1

merry osprey Dec 2, 2022, 5:29 AM

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merry osprey Dec 2, 2022, 6:15 AM

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Precalc help please!

inner lintel Dec 3, 2022, 3:42 PM

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for the first one, you have to rationalize the top by doing some algebra
for the second one, it's false, as the derivative of 8x is just 8
for the third one, find the derivatives of 6x^(-4) + x^(-2) and then plug in x =-1
for the fourth, find the derivative of x^3-5x^2, and then use y-y_1 = m(x-x_1) where m is the derivative for finding the tangent line
for the fifth, find the derivative of 3x^4-5x^3+2x^2, and then plug in x = 1 (use the power rule)
for the sixth, the limit does not exist, as the limit as x --> 3 from the right =/= the limit as x --> 3 from the left
for the seventh, factor our x^2 and then factor further to simplify the rational function
not really sure for the last, lmao

stark sandal Dec 5, 2022, 1:06 AM

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merry osprey

for the last one calculate the average rate of change from (-20,5) to (-17/22)

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so 5.67

vital cave Dec 5, 2022, 7:43 PM

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sqrt(4x+28)-4/x+3 we can just multiply by the conjugate and devide by it. so (sqrt(4x+28)-4)(sqrt(4x+28)+4)/...=4x+28-16/...=4x+12/(x+3)(sqrt(4x+28)+4) and 4x+12 is 4(x+3) so (x+3)/(x+3)*4/(sqrt(4x+28)+4)=4/sqrt(4x+28)+4

now we plug -3 and get: 4/sqrt(16)+4=1/2 which is the answer

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3rd step is illegal, the rule for d/dx(af(x)) isn't d/dx(a)d/dx(f(x)) its ad/dx(f(x)) for a constant

#Precalc help please!