Flashcards · 22 cards
Calculus (JAMB bridge)
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Rule
What is the gradient of a curve at a point?Answer
The gradient of the tangent at that point. gives it at every point.
Gradient of a curveThe gradient of the tangent at the point: rise ÷ run Rule
Differentiate .Answer
: bring the power down, then reduce the power by 1.
d/dx (a xⁿ) = na xn − 14x³ → 3 × 4x2 = 12x²bring the power down, then take 1 off the power; a constant gives 0The power ruleBring the power down, then reduce the power by 1 Know it
How do you differentiate ?Answer
Simplify first to , then differentiate: . Don't differentiate the top and bottom separately.
Rule
The derivatives of and ?Answer
and .
The cycleEach differentiation moves one step round: sin → cos → −sin → −cos → sin Rule
The chain rule? Differentiate .Answer
: outside first, then times the derivative of the inside. So .
y = (3x + 1)5dy/dx = 5(3x + 1)4 × 3differentiate the outside, leaving the inside alone, then × the inside’s derivativeThe chain ruleOutside first, then times the derivative of the inside Rule
The product rule?Answer
For : .
The product ruleThe rectangle's area uv grows by v·δu + u·δv Rule
The quotient rule?Answer
For : .
d/dx (u ⁄ v) = (v·u′ − u·v′) ⁄ v²bottom × derivative of top, minus top × derivative of bottom, all over bottom squaredThe quotient ruleBottom × top′ − top × bottom′, over bottom squared Rule
How do you find a maximum or a minimum?Answer
Solve . Then check: is a maximum and a minimum, or look at the gradient's sign either side (+ 0 − is a maximum).
Maximum and minimumFlat tangents; the gradient's sign changes + 0 − at a maximum and − 0 + at a minimum Know it
Asked for the maximum value: what do you give?Answer
The -value: put the you found back into the original function.
Rule
A circle's radius grows at . How fast does its area grow?Answer
Chain rule: .
dA/dt = dA/dr × dr/dtfrom the formula × the rate you are givenConnected ratesThe derivative from the formula, times the rate you are given Rule
From distance to velocity and acceleration?Answer
Differentiate: and .
distance sd/dt →velocity vd/dt →acceleration adifferentiate to go right; integrate to come backMotionDifferentiate distance to get velocity, and velocity to get acceleration Rule
Integrate .Answer
, for : add 1 to the power, divide by the new power, add .
∫ a xⁿ dx = a xn + 1 ⁄ (n + 1) + cadd 1 to the power, then divide by the new power; never forget + c (n ≠ −1)Integrating a powerAdd 1 to the power, divide by the new power, add c Rule
Why the , and how do you find it?Answer
Every curve has the same gradient. A given point, put into , picks out .
The + c familyEvery curve y = F(x) + c has the same gradient; the given point picks out one Know it
What is ?Rule
The area under from to ?Answer
.
Area under a curveThe area from x = a to x = b is the integral of y from a to b Know it
Part of the area is below the -axis. What do you do?Answer
Integrate each part separately and add their sizes: below the axis the integral comes out negative.
Rule
The area between two graphs?Answer
Integrate (top − bottom) between the points where they cross.
Area between two graphsIntegrate (top − bottom) between the crossing points Rule
The volume when is turned about the -axis?Answer
: each slice is a disc of radius .
Volume of revolutionEach slice is a disc of radius y and area πy² Which method?
Find the point where the curve has gradient 2.
How do you find the point?Answer
The gradient is . Set it equal to 2 to find , then put into the curve for .
Which method?
Obtain the maximum value of the function .
Which turning point is the maximum?Answer
gives . is negative at , so the maximum is there. Then work out .
From the lesson: Maxima, minima and rates of changeTry the question
Which method?
A circle with a radius of 5 cm has its radius increasing at the rate of . What will be the corresponding rate of increase in the area?
Which rule connects the two rates?Which method?
Two variables and are such that and when . Find in terms of .
How do you find ?
Keys: Space to show the answer, 1 for Not yet, 2 for Got it.