Functions 2 Question 10

11. If f(x)=cos(logx), then f(x)f(y)12fxy+f(xy) has the value

(1983, 1M)

(a) -1

(b) 12

(c) -2

(d) None of these

Show Answer

Answer:

Correct Answer: 11. (a, c)

Solution:

  1. Given, f(x)=cos(logx)

f(x)f(y)12fxy+f(xy)

=cos(logx)cos(logy)12[cos(logxlogy)

+cos(logx+logy)]

=cos(logx)cos(logy)12[(2cos(logx)cos(logy)] =cos(logx)cos(logy)cos(logx)cos(logy)=0



जेईई के लिए मॉक टेस्ट

एनसीईआरटी अध्याय वीडियो समाधान

दोहरा फलक