Hey please assist me with plotting this function, not sure why im getting indexing error

Question

Christopher Carey 2018-10-23

关闭： MATLAB Answer Bot 2021-8-20

here is my code

t=0:1:100

y1=(3/10)*(1-exp(-6*t)(cos(sqrt(14*t))+(((3*sqrt(14))/7)*sin(sqrt(14*t)))))

plot(y1,t)

Here is my error

Error: File: ap5_4.m Line: 2 Column: 14 ()-indexing must appear last in an index expression.

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Answer 1

YT 2018-10-23

编辑：YT 2018-10-23

First off

%                    \/ you missed a * sign here
y1=(3/10)*(1-exp(-6*t)(cos(sqrt(14*t))+(((3*sqrt(14))/7)*sin(sqrt(14*t)))))

Secondly, because t1 is a vector, you should use element-wise multiplication `.*` instead of `*`. So y1 should be this:

y1=(3/10)*(1-exp(-6*t).*(cos(sqrt(14*t))+(((3*sqrt(14))/7)*sin(sqrt(14*t)))))

p.s.

Next time please format your code using the Code button

Answer 2

gonzalo Mier 2018-10-23

编辑：gonzalo Mier 2018-10-23

You are missing a multiplying symbol

y1=(3/10)*(1-exp(-6*t) [.*]  (cos(sqrt(14*t))+(((3*sqrt(14))/7)*sin(sqrt(14*t)))))

So, use:

t=0:1:100
y1=(3/10)*(1-exp(-6*t).*(cos(sqrt(14*t))+(((3*sqrt(14))/7)*sin(sqrt(14*t)))))
plot(y1,t)