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shahzadjalbani
Why is the product of the gradients of 2 straight line perpendicular to each other is always equal to -1 ?? Please prove it......?
m1=1/m2 you can use two rules (straight line) to prove it. |dw:1338626026029:dw|
you can write equation of the lines perpedicular to each other in this form: ax+by=0 -bx+ay=0 this is a hint....:)
Can you prove it through trigonometry?
@myko @shirleyx Can you prove it through trigonometry?
slope = \( \tan(\theta) \) another slope = \( \tan(\theta - 90) = -\cot \theta \)
\[\cos \alpha x+\sin \alpha y =0\] \[-\sin \alpha x + \cos \alpha y =0\]
grad f1 = (cosa -sinax,sina+cosay) grad f2 = (-sina-cosax,cosa-sinay)