Indicate whether the statement is true or false. 16. Sinusoidal functions do not have any critical points. 17. The product rule does apply when multiplying exponential functions with sinusoidal functions. 18. A sinusoidal function can be differentiated only if the independent variable is measured in degrees. 19. There aren't an infinite number of tangents with a given non-zero slope to a sinusoidal curve. 20. The derivative of f (x) = 2 cos 2x is an odd function. 21. The inverse of f (x) = In x is an exponential function. 22. Another way of expressing Inx is log x. 23. The derivative of an exponential function isn't always another exponential function. 24. If y = e", then y' = ef(x). 25. The decay of a radioactive substance can be represented by more than one exponential model. 26. Simplify the expression * In( * ) + In(*+1 ] (2 marks)