two thin lenses of focal lenght 20cm and -15 cm are kept in contact. what is the focal length and power of combination. I need urgently

he made 11 calls in one day

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west

cancer risk hope this