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    How to Calculate JEE Main 2026 Marks from Answer Key: Step-by-Step Guide

    Projection Formula - Practice Questions & MCQ

    Edited By admin | Updated on Sep 18, 2023 18:34 AM | #JEE Main

    Quick Facts

    • 5 Questions around this concept.

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    In Triangle ABC, point D is on BC is such that $A D \perp B C$ and E is the middle point of BC and $b^2+2 a^2=c^2$ distance between D and E is?

    Concepts Covered - 1

    Projection Formula

    Projection Formula

    In the $\triangle A B C$,

    The projection of $A B$ on $B C$ is $B D$ and the Projection of $A C$ on $B C$ is $D C$

    Now,

    $
    \begin{aligned}
    & B D=c \cos B \text { and } D C=b \cos C \\
    & \text { and, } B C=a=B D+D C \\
    & =c \cos B+b \cos C \\
    & a=c \cos B+b \cos C
    \end{aligned}
    $
    Similarly, other projection formulas can be derived

    $
    \begin{aligned}
    & a=c \cos B+b \cos C \\
    & b=c \cos A+a \cos C \\
    & c=b \cos A+a \cos B
    \end{aligned}
    $
     

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    Projection Formula

    Mathematics for Joint Entrance Examination JEE (Advanced) : Trigonometry

    Page No. : 5.9

    Line : 21

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