Pure Year 2 Flashcards
(124 cards)
What is important to remember about sectors and small angle approximations?
Angles in radians NOT degrees
Shift
Setup
2
2
Arc length formula
r{theta}
theta must be in radians
Sector area formula
0.5r²{theta}
theta must be in radians
Area of a segment formula
(0.5r²{theta} - 0.5r²sin{theta}
theta must be in radians
When theta is small, 9{theta}²-2{theta}+1 is what?
1
theta is small so approximately 0, meaning that the first 2 terms become 0 so just leaves 1
What is a mapping?
Transforms one set of numbers into a different set of numbers
It is a function if every input has a distinct output
Is a one-to-one mapping a function?
Yes
Each input has one distinct output
Is a many-to-one mapping a function?
Yes
Each input has a distinct output
Is a one-to-many mapping a function?
No
Not every input has a distinct output
Is y=1/x a function
No
No value at 0, doesn’t map anywhere
Can be made a function by restricting domain to x≠0
Domain…
The set of X values for which the function is valid
Writen as x=a
Range…
The set of Y values that the function can take
Written as a<=f(x)<=b
How do you deal with partial fractions?
Multiply up
Knock out brackets by substituting values in to make some coefficients 0
What is a piecewise-defined funtion?
A function which consists of more than one part
When drawing:
●=less/more than or equal to
○=less/more than
What is an inverse function?
The mathematical opposite of the original function
Only exists for one-to-one functions
Y becomes X, X becomes Y, reflected in line Y=X
How do you get an inverse function?
Replace f(x) with y
Swap y and x
Rearrange to make x the subject
Swap y for f(x)
Check f(x) and not any other function notation e.g g(x)
When do inverse functions exist
One-to-one functions
What is the domain of an inverse?
The range of the ordinary function
What is the range of an inverse function?
The same as the domain of the normal function
If f(x)=sinx, the inverse function can be written as…
f-¹(x)=sin-¹x=arcsinx
Sketch the graph of y=arcsinx
State the range and domain
X Intercept: 0
Y Intercept: None
Coordinates: (-1,-90) (0,0) (1,90)
If f(x)=cosx, the inverse function can be written as…
f-¹(x)=cos-¹x=arccosx
if f(x)=tank, the inverse function can be written as…
f-¹(x)=tan-¹x=arctan
What is the modulus of a number?
It is the non negative numerical value
Also known as the absolute value
Denoted as |x|