(1) The post is not misstated.
(c) is the odd one out isn't it?
the given range for x is fine for the 1st two but not for (c)
"arcsin" is misspelled as arccsin.
what other carelessness is there?
ask your teacher for a model answer - showing working.
UPDATE: Anyway sir, how do you find out the solution of trigonometric equations through graphs? Like the one you posted in post #27.
I used gnu-octave to plot the graph ... the solution would have been the intersection of the curve with the line y=90.
The code was:
> x=0:0.0125:1;
... says to make a vector whose first entry is 0, incrementing by 1/80 until it reaches 1;
> y=acos(x)-asin(1-x);
... this is the function I want to plot a graph of: y will be in radiens;
... the result of y will be a vector the same size as x, each entry being the result of plugging the corresponding x entry into the equation.
> plot(x,y*(180/pi))
... this plots the graph - I scales the y-axis to give degrees.
... plot(X,Y) treats the two vectors X and Y as ordered pairs (Xi, Yi).
I could have plotted a line at y=90 by doing:
> plot([0,1],[90,90])
... because the plot function automatically draws a line between data points.
... plot will interpret the two vectors as the points (0,90) and (1,90).
generally: if I want to solve f(x)=c, then I could plot y=f(x) and y=c, plot both on the same axis and note the intersection ... reading x off the horizontal axis.
That is usually good for simple relations or for an approximation. For more precision, I'd use Newton-Raphson on f(x)-c=0 - using the graph to select initial values of x.
Some ability to plot the relations you are trying to solve is invaluable: it tells you what kind of solution you are aiming for. Octave is free/libre as well as free/gratis, others use Matlab or Mathematica. Only masochists use spreadsheets for stuff like this.
I guess that is pretty much all this topic exhausted - cheers.
