document.write( "Question 1199007: Draw the graph of y=cos3x-4sin x for 0°≤x<360°. Use your graph to solve the equation 3cos x-4sinx=2.5. \n" ); document.write( "
Algebra.Com's Answer #832686 by math_tutor2020(3817)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "You can use a TI83 or TI84 calculator if you have one on hand.\r
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\n" ); document.write( "\n" ); document.write( "Or better yet, I recommend using either Desmos or GeoGebra.
\n" ); document.write( "Both are faster more efficient options compared to the TI83/TI84 calculators.\r
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\n" ); document.write( "\n" ); document.write( "Here's the Desmos link to the interactive graph
\n" ); document.write( "https://www.desmos.com/calculator/i2uierdtrw\r
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\n" ); document.write( "\n" ); document.write( "Things to note about Desmos:
  • The wrench icon in the upper right corner allows you to adjust settings. Specifically we want to change radian mode into degree mode at the bottom of this settings panel.
  • The curly braces after the function tells Desmos to restrict the domain to that specific interval of 0 ≤ x < 360
  • Unfortunately there doesn't appear to be a way to change the rounding precision. It seems to be stuck at 3 decimal places. GeoGebra offers better options on this front.
The curve y = cos(3x)-4sin(x) intersects y = 2.5 at the approximate locations of
\n" ); document.write( "(214.509,2.5)
\n" ); document.write( "(298.996,2.5)
\n" ); document.write( "which tells us the approximate solutions to cos(3x)-4sin(x) = 2.5 are
\n" ); document.write( "x = 214.509
\n" ); document.write( "x = 298.996
\n" ); document.write( "This is of course when 0 ≤ x < 360
\n" ); document.write( "Without this domain restriction, there would be infinitely many solutions.
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