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Let vec a , vec b , vec c be three uni...

Let ` vec a , vec b` , ` vec c` be three unit vectors such that `| vec a+ vec b+ vec c|` and ` vec a_|_ vec bdot` If ` vec c` makes angles `alpha,beta` with ` vec a , vec b` respectively then `cosalpha+cosbeta` is equal to `3/2` (b) 1 (c) `-1` (d) None of these

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RESONANCE DPP-JEE MAINS-All Questions
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