// Numbas version: exam_results_page_options {"name": "Trig Equation 2 (translation)", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"name": "Trig Equation 2 (translation)", "tags": [], "metadata": {"description": "
solve trig equation involving a translation in given internval. with worked solutions
", "licence": "Creative Commons Attribution-NonCommercial 4.0 International"}, "statement": "Trig equation with a translation
", "advice": "\\begin{align}
sin \\left(x-\\frac{\\pi}{2} \\right) & =\\var{a} \\\\\\\\
\\left(x-\\frac{\\pi}{2} \\right) & = sin^{-1}(\\var{a})=\\var{x1n} \\\\\\\\
\\text{for $sinx$ you can find a second solution by going $\\pi-x_1$} \\\\\\\\
\\left(x-\\frac{\\pi}{2} \\right) & = \\pi-\\var{x1n}=\\var{x2n} \\\\\\\\
\\end{align}
As the range of solution goes down to $-2\\pi$ you can find two more angles by taking away $2\\pi$ from the first two angles.
\n\\begin{align}
x_3 &=\\var{x1n}-2\\pi=\\var{x3n} \\\\\\\\
x_4 &=\\var{x2n}-2\\pi=\\var{x4n}
\\end{align}
In ascending order your three solutions so far are
\n\\begin{align}
\\left(x-\\frac{\\pi}{2} \\right) & =\\var{x3n} \\text{ or } \\var{x4n} \\text{ or } \\var{x1n} \\text{ or } \\var{x2n}
\\end{align}
To find $x$ all you need to do now is add $\\frac{\\pi}{2}$
\n\\begin{align}
x=\\var{x3} \\text{ or } \\var{x4} \\text{ or } \\var{x1} \\text{ or } \\var{x2}
\\end{align}
To 3 significant figures this gives
\n\\begin{align}
x=\\var{x3_3}^c \\text{ or } \\var{x4_3}^c \\text{ or } \\var{x1_3}^c \\text{ or } \\var{x2_3}^c
\\end{align}
Solve $sin \\left(x-\\frac{\\pi}{2} \\right)=\\var{a}$ between $-2\\pi<x<2\\pi$
\n\nGive your answers in radians in ascending order and to 3 significant figures.
\n\n$x_1$=[[2]]
\n$x_2$=[[3]]
\n$x_3$=[[0]]
\n$x_4$=[[1]]
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