Posted by Subhotosh Khan on August 27, 2002 at 12:48:32:
In Reply to: Re: lots of questions lol posted by megan on August 22, 2002 at 22:47:13:
: heyheyhey...calm down lol...this is pre-calc review...mainly for the calc course i'll be taking my senior year...it's not a matter of me NOT knowing how to do the problems... it's more of a problem of FORGETTING...so it's more of a "refreshing of the memory" if you will. those weren't even all the questions...i did some on my own that i could remember. i'll point some things out that i def. need help with...
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1.) Find x such that the distance from (x, 5) to (-1, 2) is radical 65 units.
Use your "distance equation" plug in and solve.
Length of a line through (x_1, y_1) and (x_2,y_2)
= SQRT[(x_1 - x_2)^2 + (y_1 - y_2)^2
: 2.) Find the center and radius of 4x^2+4y^2-2x+8y-1=0
Rewrite in the form: (x-xo)^2+(y-yo)^2=r^2
where the co-ordinates of center is (xo,yo) and length of radius is'r'
for #2...i just need the formula basically...
: 3.) Write the equation in standard form of the circle which has (3, 7) and (5, -3) as endpoints of its diameter.
d=2r and the center is the center of d.coordinates of md-point (x_m,y_m) of a line through (x_1, y_1) and (x_2,y_2)is:
x_m = (x_1+x_2)/2
y_m = (y_1+y_2)/2
: for #3...i honestly don't remember doing this...you just need the same forumla for #2 right??
: 4.) Find all intercepts: y= (x-1)/(x+3)
intercepts are when y=0. then solve for x
for y intercept x=0 so y =(0-1)/(0+3) = -1/3
: #4...not sure...do i plug in certain numbers? ahhh stupid brain! lol
: 5.) If f(x)= 1/sqrt(x) and g(x)= x^2-4, find g(f(x))
:
Just do what it says.
#5 i think i have an idea now...
: 6.) Find the domain of f(x)= 1/sqrt(3+2x)
Domain is valid x values. 'sqrt'functions must have positive arguements to have solution in real domain.
: #6 ::shrug::
: 7.) Solve for x (0 equal or less than x equal or less than 2pi) 2cos^2 x-5cosx=3
let y=cosx solve for y then get x
#7 and 8 i did, but it just didn't look correct...i wasn't sure if i needed to remember the unit circle to do it...
: 8.) If sinx= 2/5 find a.) sin2x b.) cos2x
use trig identies
: 9.) Find the zero(s) of: f(x)=x^3-x^2+x+3
Factor - find at what values of 'x' the value of f(x)=0
f(x)=x^3-x^2+x+3=(x+1)(x^2-2x+1)=(x+1)(x-1)^2
#9 i honestly have no clue
: 10.) State the domain and range of the inverse sine function.
Look at a graph.
#10 i gotta scrounge thru my old notes...:
11.) Evaluate w/o a calculator:
: a.)csc (4/3pi)
: b.)cos(arcsin ( - 3/5 )
: c.)cos 135 degrees cos 15 degrees - sin 135 degrees sin 15 degrees
: d.)sin^-1 rad 3
: -----
: 2
Trig idenities using things you know i.e.
sin(pi/4) etc...
#11 same problem like 7 and 8
: 12.) Sketch the graph of 2sin(2x-pi) for 2 periods. Be sure to include values on each axis.
take sin and compress, shift then amplify
#12 i pretty much think all i need is the formula...same with #15
: 13.) Solve (x+3)^2 - (2x-1)(x-3)=18
I see only x^2 here. expand, rewrite, then comlpet the square it will be good for you
: 14.) Rewrite rad x y cube root as a single term,
: ------------------ using only pos. and
: (x+2)^3 4th root neg. exponents.
x^-1=1/x
#14 i have no idea
: 15.) What is the volume of a cube if its total surface are is 150 in^2?
What is the lagrest number on a die, and what is the length of one side?
: 16.) Do the points A(6, 4), B(4, -3) and C(-2, 3) form an isosceles triangle? A right triangle? Verify your answer analytically and explain in one or two sentences.
Plot. and check with a^2+b^2=c^2 and check if a=b=c
#16 do i need a formula for this as well??