And sin1000x + cos2008x Its maximum value will be 1 , as both sinx and cosx range are less than equal to one , so if a number less than 1 has exponents very high like 1000 or 2008 , then it will eventually lead to very small value and ultimately zero. So the smallest value will be zero and maximum value will be 1 , when x = 0 or 90 degree . simple hope u like it