Question

tan 50° = p/q
হলে, cos40° -এর মান কত
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Answer 1

Answer:

Heya buddy...................❤✌

Given,

tan 50° = p/q

=> sin 50°/ cos 50° = p/q

=> sin ( 90° - 40°)/ cos 50° = p/q

=> cos 40° / cos 50° = p/q

=> cos 40° = (p/q) × cos 50°

=> cos 40° = 0.643 p/q

আশা করছি এটা helpful.....☺

Answer 2

$\underline{\blacksquare\:\:\:\footnotesize{\red{ছবি}}}$

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$\setlength{\unitlength}{1.6mm}\begin{picture}(30,20)\linethickness{0.3mm}\put(0,0){\line(0,1){30}}\put(0,0){\line(1,0){22.5}}\put(0,30){\line(3,-4){22.5}}\put(16.5,1){ 50^{\circ} }\put(0.5,23){ 40^{\circ} }\put(-3,30){ A }\put(-3,-0.5){ B }\put(23,-0.5){ C }\put(3,0){\line(0,1){3}}\put(0,3){\line(1,0){3}}\put(-2,15){ p }\put(12,-2){ q }\put(13,15){ \sqrt{p^2+q^2} }\end{picture}$

$\setlength{\unitlength}{1.0 cm}}\begin{picture}(12,4)\linethickness{1 mm}\put(1,1.2){\line(1,0){6.8}}\end{picture}$

$\underline{\blacksquare\:\:\:\footnotesize{\red{সমাধান}}}$

$\footnotesize{আমরা \: জানি , \:\:\tan50\degree=\dfrac{উচ্চতা}{ভূমি}=\dfrac{AB}{BC}}$

$\footnotesize{বা ,\:\:\tan50\degree=\dfrac{AB}{BC}}$

$\footnotesize{বা ,\:\:\dfrac{p}{q}=\dfrac{AB}{BC}}$

$\footnotesize{এখন \:ছবি \:অনুযায়ী\:\:AB=p\:\:এবং\:\:BC=q}$

$\footnotesize{\text{ এখন , পিইথাগরাস এর সূত্র প্রয়োগ করে পাই}}$

$\footnotesize{\therefore\:\:AC^2=AB^2+BC^2}$

$\footnotesize{বা ,\:\:AC^2=p^2+q^2}$

$\footnotesize{বা ,\:\:\red{AC=\sqrt{p^2+q^2}}}$

$\footnotesize{\therefore\:\:\cos40\degree=\dfrac{ভূমি}{অতিভুজ}=\dfrac{AB}{AC}}$

$\footnotesize{বা ,\:\:\cos40\degree=\dfrac{AB}{AC}}$

$\footnotesize{বা ,\:\:\cos40\degree=\dfrac{p}{\sqrt{p^2+q^2}}}$

$\footnotesize{বা ,\:\:\red{\boxed{\cos40\degree=\dfrac{p}{\sqrt{p^2+q^2}}}}}$

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