Find g(f(x)) where g(x)=2x+4 and f(x)=x^2+1.
With functions of functions you work from the inside out, so you substitute the function f(x) for the x in g(x). We know that f(x)=x2+1 and g(x)=2x+4. In this question you therefore replace the x in 2x+4 with x2+1. This leads to g(f(x))=2(f(x))+4, or g(f(x))=2(x2+1)+4. The next step is to expand the brackets, giving 2x2+2+4, and then to collect like terms to give g(f(x))=2x2+6.
GM
Related Maths GCSE answers
All answers ▸There are only 7 blue pens, 4 green pens and 6 red pens in a box. One pen is taken at random from the box. Write down the probability that this pen is blue.
Natasha has two bags of fruit. both bags have the same number of fruit in total. 1/3rd of the fruit in bag 1 are apples and 15% of the fruit in bag 2 are apples. There are 20 apples in bag 1, how many apples are in bag 2?
Work out the gradient and y-intercept of the straight line with points A(3,8) and B(-2,-7)
These are the selling prices of 5 houses in 2007: £145 000, £170 000, £215 000, £90 000, £180 000. Work out the mean selling price.