For what value of k for which the quadratic equation 2x^2+ kx-8=0 has real roots
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According to Quadratic formula :-
If D=0, polynomial will have equal real roots
If D>0, polynomial will have Unequal real roots
If D<0, polynomial will have Non-real roots.
Hence for the question D shud be either greater than or = 0. Taking the least required one.
Therefore ,
D = b2 - 4ac =0
= K2 - 4(2)(8) = 0
= K2 - 64 = 0
= K2 = 64
Hence K = +/- 8
Hence for the equation to have real roots , K shud be either greater than or equal to 8 or lesser than or equal to -8.
If D=0, polynomial will have equal real roots
If D>0, polynomial will have Unequal real roots
If D<0, polynomial will have Non-real roots.
Hence for the question D shud be either greater than or = 0. Taking the least required one.
Therefore ,
D = b2 - 4ac =0
= K2 - 4(2)(8) = 0
= K2 - 64 = 0
= K2 = 64
Hence K = +/- 8
Hence for the equation to have real roots , K shud be either greater than or equal to 8 or lesser than or equal to -8.
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