diilip

“tipped down. She slipped her right hand in her pocket, pressed the buzzer with her left. Nadine, she thought,”
― J.D. Robb, Obsession in Death

“average electric field in a spherical control volume | 119 R θ x′ x Figure 5.9 Geometry used to evaluate the surface integral in (5.41). and hence ¿ SR dS |x − x | = żπ 0 (2πRsinθ)(cos θ x/ x )(R dθ) (Rcos θ − |x |)2 + (Rsinθ)2 = 2πR2 x |x | ż 1 −1 χ dχ R2 + |x | 2 − 2R|x |χ , (5.42) where χ = cos θ. The integral on the second line of (5.42) may now be evaluated using the indefinite integral ż χ dχ √a − bχ = 2 b2 a − bχ 3 − a a − bχ, and after a little work we obtain ¿ SR dS |x − x | = ⎧ ⎨ ⎩ 4π 3 x, x < R, (5.43a) 4π 3 R3 |x| 3 x, x > R. (5.43b) Thus our integral of E over VR becomes ż VR E(x)dx = VR 4πε0 ż |x|>R ρe(x) (−x) |x | 3 dx − 1 3ε0 ż VR x ρe(x )dx, (5.44) or equivalently ż VR E(x)dx = VREqout(0) − pqin 3ε0. (5.45) We have arrived back at (5.39), albeit after a great deal of integration. Although this particular derivation of (5.39) is rather long-winded, some ofthe results we have deduced on route, such as (5.43a, b), will prove useful when it comesto our discussion of magnetostatics.”
― Peter A. Davidson, An Introduction to Electrodynamics

“elevator doors opened; the girls clumped out, laughing”
― J.D. Robb, Obsession in Death

“I always thought of myself as a humanities person as a kid, but I liked electronics,” he said. “Then I read something that one of my heroes, Edwin Land of Polaroid, said about the importance of people who could stand at the intersection of humanities and sciences, and I decided that’s what I wanted to do.” It was as if he were suggesting themes for his biography (and in this instance, at least, the theme turned out to be valid). The creativity that can occur when a feel for both the humanities and the sciences combine in one strong personality was the topic that most interested me in my biographies of Franklin and Einstein, and I believe that it will be a key to creating innovative economies in the twenty-first century.”
― Walter Isaacson, Steve Jobs