# Thread:

1. ## finding and angle x in radians?

Find an angle x in radians such that 8pi<x<9pi and cosx=1/2

What is this question asking for? I came up with pi/3, but I don't think that's in between 8 and 9 pi. Can anyone explain? Thanks

2. Originally Posted by captaintoast87
Find an angle x in radians such that 8pi<x<9pi and cosx=1/2

What is this question asking for? I came up with pi/3, but I don't think that's in between 8 and 9 pi. Can anyone explain? Thanks
Remember that $\cos{x}$ is periodic with a a period of $2\pi$ which means you get your original answer of $\frac{\pi}{3}$ and add 4 lots of $2\pi$ (this is 4 periods) to give you an answer of $8\pi + \frac{\pi}{3} = \frac{25\pi}{3}$
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 5, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "github"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "english_confidence": 0.9791679978370667, "perplexity_flag": "middle"}