Plzz helppp i don't understand
2 answers:
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Answer:
The given function symmetric about the y-axis.
Step-by-step explanation:
The given function is
.... (1)
1. Symmetry about the x-axis: If the point (r, θ ) lies on the graph, then the point (r,-θ ) or (-r, π - θ ) also lies on the graph.
2. Symmetry about the y-axis: If the point (r, θ ) lies on the graph, then the point (r,π - θ ) or (-r, -θ ) also lies on the graph.
3. Symmetry about the origin: If the point (r, θ ) lies on the graph, then the point (-r, θ ) or (r, π + θ ) also lies on the graph.
Put (r, -θ ) in the given function.
Therefore it is not symmetric about x-axis.
Put (-r, -θ ) in the given function.
Therefore it is symmetric about y-axis.
Put (-r,θ ) in the given function.
Therefore it is not symmetric about the origin.
Answer:
4 ohms
Step-by-step explanation:
The question is "In two minutes a current of 5 amps develops 1,200 heat units in a wire of 8 ohms resistance. What resistance does a similar wire have, which develops 6,000 heat units with a current of 10 amps in 5 minutes?"
Current, I₁ = 5 A
Heat, Q₁ = 1200 units
Resistance, R₁ = 8 ohms
Time, t₁ = 2 min = 120 s
New heat, Q₂ = 6000 units
Current, I₂ = 10 A
New time, t₂ = 5 min = 300 s
We need to find the new resistance.
Heat developed is given by :
So, the new resistance is 4 ohms.