# Matlab Built-In Functions

Matlab → Basics → Variables → Built-In Functions

Suppose we want to find the square root of 16. It could easily be done in Matlab using the command >> sqrt(16). It shows the answer 4 when you press the Enter key. For example,

Command Window
>> sqrt(16) ans = 4

Matlab has several useful built-in functions. A few of them are listed in the following Table.

 Mathematics Command Answer $\sqrt{(80)}$ $\sqrt{(80+1)}$ >> sqrt(81) >> sqrt(80+1)  9 9 $e^5$ $e^{-6}$ >> exp(5) >> exp(-6) 148.4132 0.0025 $|-10|$ >> abs(-10) 10 $4!$ $5!$ >> factorial(4) >> factorial(5) 24 (4×3×2×1=24) 120 (5×4×3×2×1=120) $ln1000$ $log1000$ >> log(1000) >> log10(1000) 6.9078 3 $\pi$ >> pi 3.1416 $sin\Big(\frac{\pi}{6}\Big)$ $sin30^0$ >> sin(pi/6) >> sind(30) 0.5000 0.5000 What is the remainder when 33 is divided by 5? What is the remainder when 134 is divided by 9? >> rem(33,5) >> rem(134,9) 3 4

Example Suppose \$2,000 is invested at a rate of 8% per year compounded continuously. How much will be the amount after:
(a) 4.2 years
(b) 5 years and 2 months

Solution:
(a) When $t=4.2$, the Matlab code is

>> P=2000; r=0.08; t=4.2; >> A=P*exp(r*t) A = 2798.678

(b) When $t=5.1667$ (because 5 years and 2 months = $5+\frac{2}{12}=5.1667$), the Matlab code is

>> P=2000; r=0.08; t=5.1667; >> A=P*exp(r*t) A = 3023.706

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