If a, b, c are the sides of a triangle and A, B, C are the opposite angles, find ∂A/∂a, ∂A/∂b, ∂A/∂c by implicit differentiation of the Law of Cosines.

Beryl states that insulation with the smallest possible thermal conductivity is best to keep a house warm in winter, but worst for keeping a house cool in summer. sapphire insists the reverse is true: low thermal conductivity is good in the summer, but bad in the winter. which one, if either is correct? a. beryl, because low thermal conductivity results in low heat transfer. b. beryl, because low thermal conductivity results in high heat transfer. d. sapphire, because low thermal conductivity results in high heat transfer. e. neither, because low heat transfer is desirable both in summer and in winter.

When can a theory be modified if a new type of technology allows for new observations that raise new questions? a-immediately, while the questions about the theory are being asked b-after new hypotheses related to the theory are tested in experiments c-only after the new observations disprove all parts of the theory d-while scientists begin to think about how the theory could improve

An object that weighs 75n is pulled on a horizontal surface by a horizontal pull of 50 n to the right. the friction force on this object is 30 n to the left. what is the acceleration of the object?