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how do i know when to use the preterite and when to use the imperfect tense in spanish ?

The imperfect tense and the Preterite tenses are the two main past tenses in Spanish, yet they are used in different situations. The preterite is used to talk about completed events or actions in the past wi...
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Answered by Islay S. • Spanish tutor
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If a curve has equation y = (-8/3)x^3 - 2x^2 + 4x + 18, find the two x coordinates of the stationary points of this curve.

The first step in solving this question is to differentiate equation y with respect to x. To differentiate a given 'x' term in an equation use the following method --> x n becomes nx (n-1) .y = (-8/3)x 3 ...
RT
Answered by Robyn T. • Maths tutor
3639 Views

Why does the breathing rate not return to normal after vigorous exercise?

During vigorous exercise, muscles are not supplied with enough oxygen. This means that cells have to respire anaerobically. Anaerobic respiration involves no oxygen. This leads to a build-up of lactic acid i...
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A curve has equation y=x^2 + 2x +5. Find the coordinates of the point at which the gradient is equal to 1.

dy/dx= 2x+2 , gradient is equal to 1 so dy/dx also equals 1.1=2x+2-1=2xx=-1/2plug this value of x into the equation to get y=17/4
NL
Answered by Nikhil L. • Maths tutor
4190 Views

Find the derivative, dy/dx, of y = 8xcos(3x).

Let u= 8x then du/dx = 8Let v= cos(3x) then dv/dx = -3sin(3x)Therefore using the product rule: dy/dx = (cos(3x))(8) + (8x)(-3sin(3x))So dy/dx = 8cos(3x) - 24xsin(3x) .
JC
Answered by Joshua C. • Maths tutor
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