181k views
4 votes
Find a numerical value of one trigonometric function of x for Cscx = sin xtan x + COS X.

User Calle
by
3.3k points

1 Answer

5 votes

Answer:

tan(x) = 1

Explanation:

I find the least tedious way to answer questions like this is to use a graphing calculator to graph a function that is zero for the desired x. We can write that function by subtracting csc(x) from both sides of the equation:

0 = sin(x)tan(x) +cos(x) -csc(x)

The graph shows a solution to be x=π/4, corresponding to 45°. The values of the trig functions for this angle are ...

  • sin(π/4) = (√2)/2
  • cos(π/4) = (√2)/2
  • tan(π/4) = 1
  • csc(π/4) = √2

_____

An algebraic solution might go like this.

1/sin(x) = sin(x)·tan(x) +cos(x)

Multiplying by sin(x), we get ...

1 = tan(x)·sin(x)^2 + sin(x)cos(x)

Substituting for sin(x)^2, this is

1 = tan(x)(1 -cos(x)^2) +sin(x)cos(x)

1 = tan(x) - (sin(x)/cos(x))·cos(x)^2 +sin(x)cos(x) . . . using tan(x) = sin(x)/cos(x)

1 = tan(x)

Find a numerical value of one trigonometric function of x for Cscx = sin xtan x + COS-example-1
User Singe Batteur
by
3.2k points