Question

Sabendo que o valor de log 30 = a e log 24 = b , 6 15 assinale a opção que apresenta o valor de log 60 em 12 função de a e b. ab+b-1

Accepted Answer

B) ab+b+l b+3-ab

Answer

A) ab-a+1 2ab+2a-1

Answer

C) ab-1 2a-b-2-ab

Answer

D) ab-1 1+a+b

Answer

E) 2+a Página: 7/12 TEXTI Read lhe text below and answer questions 23 to 26. Robo-penguin: how artificial birds are relaying the secrets of ocean currents [1] lf it looks like a penguin and swims like a penguin - but it's actually a robot - then it must be the lates! advance in marine sensory equipment. [2] The Quadroin is an autonomous underwater vehicle (AUV): a 3D-printed self-propelled machine designed to mimic a penguin in order to measure lhe properties of oceanic eddies. [3] li was developed by Burkard Baschek while head of Germany's lnstitute of Coastal Ocean Dynamics ai the Helmholtz Centre Hereon after he watched more than $20,000 of his equipment sink to the bottom of lhe Pacific Ocean. [4] Eddies are small ocean currents that other research methods have struggled to capture. They influence all lhe animais and plants in lhe seas as well as lhe Earth's climate, driving roughly 50% of ali phytoplankton production. The base of the marine food chain, phytoplankton and other marine plants such as kelp and algal plankton also produce up to 70% of atmospheric oxygen. [5] Despite:their significance, eddies are poorly understood within lhe 0scientific community because they are small; some are just 10 metres across, and they have an average lifespan of12 hours, posing a huge challenge for ocean observations. Few detailed measurements even exist. [6] Baschek first developed a device with about 20 sensors attached to a rope, to be towed behind a ship to measure key oceanographic variables in lhe eddies - such as temperature, salinity, pressure, chlorophyll and oxygen. But lhe rope would catch on rocks, fishing nets or containers - sending ali lhe data to lhe seabed. [7] "The only way to avoid such underwater dangers was to develop a device which can do these measurements without being tied to a rope," says Baschek. [8] The solution carne from Rudolf Bannasch and his team at the Berlin-based company Evologics, which specialises in bionics based on natural evolution. Bannasch knew exaclly what Baschek needed: a penguin. [9] "Penguins provide a shape with optimal aerodynamic characteristics," says Bannasch. His studies in wireless underwater navigation and communication systems suggest that penguins are 20% to 30% more aerodynamic than anything designed in a laboratory, ideal for lhe highspeed measurements Baschek sought. [10] ln April, lhe first Quadroin prototype - lhe name derives from "quadro", after lhe four propellers that move lhe AUV, and "penguin" - had its maiden voyage in a lake near Berlin. lt has a maximum speed of eight knots (9.2 mph) and uses lhe sarne sensors that used to be towed on a rope. The Quadroin, however, can float freely through the water, avoiding obstructions, to depths of 150 metres. [11] One element in lhe study of eddies that has worried scientists is lha! they need to be measured in multiple locations simultaneously. Bannasch and his colleagues are working to create two more artificial penguins that would swim in unison and communicate with each other. [12] "We developed lhe first singing underwater modems so that lhe Quadroins will be able to send and receive chirping signals similar to those of dolphins," says Bannasch. [13] As for losing !hem to lhe bottom of lhe ocean, lhe artificial penguins have a final trick lha! also mimics their real-life counterparts: if lhe electronics fail and the sensors go dark, they float. (Adapted from: https://www.theguardian.com)

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