15. [-/2 Points] DETAILS SALGTRIG4 4.5.098.MI. MY NOTES PRACTICE ANOTHER Environmental scientists measure the intensity of light at various depths in a lake to find the "transparency" of the water. Certain levels of transparency are required for the biodiversity of the submerged macrophyte population. In a certain lake the intensity of light at depth x is given by I = 8e-0.001x where I is measured in lumens and x in feet. (a) Find the intensity I at a depth of 45 ft. (Round your answer to two decimal places.) lumens (b) At what depth has the light intensity dropped to I = 4? (Round your answer to one decimal place.) ft Need Help? Read It Watch It Master It